These Sourdough Vanilla Custard Donuts are soft, fluffy, golden, and filled with a silky homemade vanilla custard. The dough develops a wonderful depth of flavor from sourdough fermentation, while the creamy custard provides a rich and smooth contrast to the lightly crisp exterior.
Unlike ordinary yeast donuts, sourdough donuts rely on an active sourdough starter for fermentation. This gives the dough a subtle tang and beautifully tender texture. The dough does require some patience, but most of the work is hands-off while the starter does its job.
Once fried, the donuts are lightly coated in sugar and filled with generous spoonfuls of vanilla custard. They make a fantastic weekend breakfast, brunch treat, afternoon dessert, or special homemade pastry.
Why You’ll Love These Donuts
These donuts combine three irresistible qualities: fluffy sourdough pastry, crisp golden edges, and creamy vanilla custard.
The sourdough fermentation gives the dough a complex flavor that you simply cannot get from a quick donut recipe. The homemade custard is smooth, rich, and fragrant with vanilla.
You can also prepare the dough the night before and allow it to ferment slowly in the refrigerator. This makes the recipe more convenient and can develop even more flavor.
Although the recipe takes time, the final result is well worth the wait.
Ingredients
For the Sourdough Donut Dough
- 100 g active sourdough starter, 100% hydration
- 500 g all-purpose or bread flour
- 180 g whole milk, lukewarm
- 2 large eggs
- 60 g granulated sugar
- 60 g unsalted butter, softened
- 8 g salt
- 1 teaspoon vanilla extract
For the Vanilla Custard
- 500 ml whole milk
- 4 large egg yolks
- 90 g granulated sugar
- 35 g cornstarch
- 1 teaspoon vanilla extract
- 25 g unsalted butter
- Pinch of salt
For Frying and Finishing
- Neutral frying oil, such as vegetable, canola, or sunflower oil
- Granulated sugar, for coating
Before You Begin
For the best sourdough donuts, make sure your starter is active and healthy.
An active starter should be bubbly, smell pleasantly fermented, and rise noticeably after feeding. Ideally, use it when it is near its peak activity.
A weak or inactive starter may produce dense donuts.
Because sourdough fermentation depends on temperature, your timing can vary. A warm kitchen may shorten fermentation, while a cool kitchen may require considerably more time.
Instead of following the clock alone, pay attention to the appearance and texture of the dough.
Making the Sourdough Dough
Place the active sourdough starter, lukewarm milk, eggs, sugar, and vanilla extract into a large mixing bowl.
Whisk until the ingredients are reasonably well combined.
Add the flour and salt.
Mix with a wooden spoon or dough whisk until a shaggy dough forms.
Cover the bowl and let the dough rest for approximately 20–30 minutes.
This short resting period gives the flour time to hydrate and makes the dough easier to develop.
Developing the Dough
After the rest, begin incorporating the softened butter.
Add the butter gradually, working it into the dough after each addition.
The dough will initially feel sticky and somewhat messy. Continue kneading until the butter is fully incorporated.
You can knead by hand or use a stand mixer fitted with a dough hook.
Knead until the dough becomes smoother, elastic, and able to stretch without immediately tearing.
Because this is a rich dough containing eggs, milk, butter, and sugar, it may take longer to develop than a basic sourdough bread dough.
Do not add large amounts of extra flour simply because the dough feels sticky. Too much flour can make the finished donuts heavy.
A slightly tacky dough is perfectly acceptable.
Bulk Fermentation
Transfer the dough to a lightly greased bowl.
Cover it and allow it to ferment at room temperature.
Depending on your starter and kitchen temperature, bulk fermentation may take approximately 4–8 hours.
The dough does not necessarily need to double completely.
Look for a noticeable increase in volume, a smoother appearance, and some airiness throughout the dough.
If your kitchen is cool, fermentation can take longer.
You can also perform one or two gentle stretch-and-folds during the first couple of hours if the dough needs additional strength.
Overnight Fermentation
For convenience and extra flavor, you can refrigerate the dough overnight after bulk fermentation.
Cover the bowl tightly and refrigerate for approximately 8–12 hours.
The cold dough will become easier to handle and cut.
The following day, remove it from the refrigerator and allow it to sit at room temperature briefly before shaping if it feels extremely firm.
Preparing the Vanilla Custard
The vanilla custard can be prepared while the dough is fermenting or the day before.
Place the egg yolks, sugar, cornstarch, and salt in a medium saucepan.
Whisk until smooth.
Gradually add the milk while whisking constantly to prevent lumps.
Place the saucepan over medium-low to medium heat.
Cook while whisking continuously.
As the mixture heats, it will gradually thicken.
Once it becomes thick and creamy and begins bubbling gently, continue cooking for approximately 30–60 seconds while whisking.
Remove the saucepan from the heat.
Add the vanilla extract and butter.
Whisk until the butter melts completely and the custard is smooth.
Transfer the custard to a clean bowl.
Press plastic wrap directly onto the surface to prevent a skin from forming.
Refrigerate until completely chilled.
Rolling and Cutting the Donuts
Place the fermented dough on a lightly floured work surface.
Gently roll it to approximately 1.5 cm thick.
Try not to press all of the air out of the dough.
Using a round donut or biscuit cutter approximately 7–8 cm wide, cut individual dough rounds.
Transfer the rounds to parchment-lined baking sheets.
Leave enough space between each donut for expansion.
Gather the scraps and gently re-roll them once.
Avoid repeatedly working the scraps because excessive handling can make the donuts tougher.
Final Proof
Cover the shaped donuts loosely with plastic wrap or a clean kitchen towel.
Allow them to proof at room temperature until they look noticeably puffy and light.
This may take approximately 1–3 hours, depending on the temperature and strength of your starter.
A properly proofed donut should feel airy and soft when gently touched.
Do not rush this stage.
Under-proofed donuts can become dense, while excessive proofing can make the dough difficult to handle and may cause it to collapse.
Heating the Oil
Pour neutral oil into a deep, heavy-bottomed pot.
Use enough oil to allow the donuts to float freely.
Heat the oil to approximately 175°C (350°F).
A kitchen thermometer is strongly recommended because maintaining the correct temperature is one of the keys to successful donuts.
If the oil is too hot, the outside can brown before the center cooks.
If the oil is too cool, the donuts can absorb excessive oil and become greasy.
Maintain the temperature as consistently as possible while frying.
Frying the Donuts
Carefully lower a few donuts into the hot oil.
Do not overcrowd the pot.
Fry each donut for approximately 1½–2 minutes per side, depending on its thickness and oil temperature.
Turn them gently using a slotted spoon or chopsticks.
They should become golden brown and puffed.
Once cooked, transfer them to a wire rack lined with paper towels.
Allow excess oil to drain.
Continue with the remaining donuts, allowing the oil to return to the correct temperature between batches.
Coating the Donuts
While the donuts are still warm, gently roll them in granulated sugar.
The sugar will stick beautifully to the slightly warm surface.
If you prefer a less sweet finish, you can skip the sugar coating and dust the donuts lightly with powdered sugar after filling.
Filling With Vanilla Custard
Once the donuts have cooled enough to handle, transfer the chilled vanilla custard to a piping bag fitted with a small round tip.
Use a skewer, chopstick, or small knife to create a hole in the side of each donut.
Insert the piping tip into the opening.
Squeeze gently until you feel the donut becoming heavier and the custard begins to fill the interior.
Do not overfill because too much pressure can cause the donut to split.
Repeat with all the donuts.
For an extra-special presentation, pipe a small swirl of custard on top of each donut before serving.
How to Get Extra-Fluffy Donuts
The biggest secret to fluffy sourdough donuts is proper fermentation.
Make sure your starter is active before beginning.
Do not add excessive flour during mixing.
Allow the dough enough time to ferment.
Pay attention to the dough rather than relying entirely on a fixed timetable.
During final proofing, wait until the donuts look visibly puffy.
Another important factor is frying temperature. Consistent oil temperature helps the donuts cook evenly while maintaining their light interior.
Common Mistakes to Avoid
Using an Inactive Starter
If your starter is not active, the donuts may not rise properly.
Adding Too Much Flour
Sticky dough can tempt you to add flour, but excessive flour produces dense donuts.
Under-Proofing
If the shaped donuts are still small and firm when fried, they may not have finished their final proof.
Over-Proofing
Over-proofed dough can become fragile and collapse during frying.
Incorrect Oil Temperature
Use a thermometer whenever possible.
Overcrowding the Pot
Too many donuts can dramatically reduce the oil temperature.
Fry in small batches.
Vanilla Custard Tips
For a perfectly smooth custard, whisk constantly while cooking.
Cornstarch helps the custard thicken, but it must be heated sufficiently to activate.
Do not cook the custard over extremely high heat because the eggs can scramble.
If your custard develops a few lumps, immediately pass it through a fine-mesh sieve while it is still warm.
Always cool the custard completely before filling the donuts.
Flavor Variations
Chocolate Custard Donuts
Replace approximately 20 g of cornstarch with unsweetened cocoa powder and add a little extra sugar if desired.
Lemon Custard Donuts
Add finely grated lemon zest to the custard for a bright citrus flavor.
Cinnamon Sugar Donuts
Instead of plain sugar, combine granulated sugar with a little cinnamon for coating.
Strawberry Custard Donuts
Add finely chopped fresh strawberries to the custard just before filling, or serve the donuts with fresh berries.
Orange Vanilla Donuts
Add a small amount of finely grated orange zest to the dough or custard.
Can I Bake These Donuts?
These donuts are designed to be fried because frying produces their classic golden exterior and fluffy interior.
You can experiment with baking, but the texture will be different.
If baking, place the proofed donuts on a parchment-lined baking tray and bake at approximately 180°C (350°F) until lightly golden and cooked through.
Brush them with melted butter after baking and coat with sugar if desired.
Storage
These donuts are best enjoyed on the day they are made.
Because they contain homemade custard, store filled donuts in the refrigerator.
Place them in an airtight container and consume within approximately 1–2 days for the best quality.
The refrigerator can cause the donut texture to become slightly firmer, so allow them to sit at room temperature briefly before serving if desired.
For food safety, do not leave custard-filled donuts at room temperature for extended periods.
Can You Freeze Them?
For best results, freeze the fried donuts before filling them with custard.
Allow the donuts to cool completely.
Place them on a baking sheet and freeze until firm.
Transfer them to a freezer-safe container or bag.
Thaw at room temperature, then fill with freshly prepared vanilla custard.
Freezing the custard separately can also be done, although the texture may change slightly after thawing.
Serving Suggestions
These sourdough custard donuts are delicious with coffee, tea, or hot chocolate.
For brunch, arrange them on a serving platter with fresh berries.
For dessert, serve them with a small scoop of vanilla ice cream or a spoonful of berry sauce.
You can also dust them with powdered sugar immediately before serving for a beautiful bakery-style finish.
Frequently Asked Questions
Can I use sourdough discard?
For this recipe, an active sourdough starter is recommended because the starter needs to provide the fermentation and rise. Discard alone will not reliably produce fluffy donuts unless combined with another leavening method.
Why are my donuts dense?
Dense donuts are usually caused by an inactive starter, insufficient fermentation, under-proofing, excessive flour, or frying at an unsuitable temperature.
Can I prepare the dough overnight?
Yes. An overnight cold fermentation is an excellent option and can make the timing easier.
Can I make the custard ahead?
Absolutely. The custard can be made a day ahead and refrigerated until needed.
How do I know when the oil is ready?
The ideal temperature is approximately 175°C (350°F). A kitchen thermometer is the most reliable way to check.
Why are my donuts greasy?
Oil that is too cool can cause donuts to absorb more oil. Overcrowding the pan can also lower the temperature.
Can I use bread flour?
Yes. Bread flour can provide additional structure and chewiness. All-purpose flour creates a slightly softer texture.
Recipe at a Glance
Prep Time: 45 minutes
Fermentation: 5–10 hours, depending on conditions
Final Proof: 1–3 hours
Frying Time: Approximately 15–20 minutes
Total Time: Varies with fermentation
Yield: Approximately 14–16 donuts
Frying Temperature: 175°C (350°F)
Final Thoughts
These Sourdough Vanilla Custard Donuts are a wonderful baking project for anyone who loves homemade pastries. The sourdough dough brings a subtle tang and depth of flavor, while the homemade vanilla custard adds a smooth, creamy center.
The key to success is patience. Give the sourdough starter enough time to ferment the dough, allow the shaped donuts to become properly puffy before frying, and maintain a steady oil temperature.
For the best experience, fill the donuts shortly before serving and enjoy them while the pastry is fresh and tender. A simple sugar coating is all they need, although powdered sugar, cinnamon sugar, chocolate custard, or fresh berries can make them even more special.
Once you master the basic recipe, you can experiment with different fillings and toppings to create your own bakery-style sourdough donuts at home.
