This Sourdough Cloud Cake is incredibly light, soft, and airy, similar to a Japanese soufflé cheesecake but without the cream cheese. The sourdough discard adds a subtle tang, making the cake perfectly balanced—not overly sweet and wonderfully fluffy.
Prep Time
- Prep: 25 minutes
- Bake: 65–75 minutes
- Cooling: 1 hour
- Total: About 2½ hours
Servings: 8
Ingredients
Batter
- 4 large eggs, separated
- 100 g (½ cup) sourdough discard (unfed, room temperature)
- 60 ml (¼ cup) whole milk
- 40 g unsalted butter, melted
- 60 g cake flour (or all-purpose flour, sifted)
- 20 g cornstarch
- 70 g granulated sugar
- 1 teaspoon vanilla extract
- ½ teaspoon lemon juice or cream of tartar
- Pinch of salt
Optional Toppings
- Powdered sugar
- Fresh berries
- Whipped cream
- Lemon zest
Equipment
- 6-inch (15 cm) round cake pan
- Parchment paper
- Large roasting pan (for water bath)
- Electric mixer
Instructions
Step 1: Prepare the Oven
- Preheat oven to 300°F (150°C).
- Grease the cake pan.
- Line the bottom and sides with parchment paper.
- Wrap the outside of the pan with aluminum foil to prevent water from leaking in.
Step 2: Make the Base Batter
- In a bowl, whisk together:
- Sourdough discard
- Milk
- Melted butter
- Vanilla
- Add the egg yolks one at a time.
- Sift in the cake flour and cornstarch.
- Mix until completely smooth.
Step 3: Whip the Egg Whites
- Place egg whites in a clean bowl.
- Add lemon juice.
- Beat until foamy.
- Gradually add the sugar in three additions.
- Continue beating until stiff glossy peaks form.
Step 4: Fold the Batter
- Fold one-third of the whipped egg whites into the batter.
- Add the remaining whites in two batches.
- Fold gently using a spatula.
- Do not overmix or the cake will lose its airy texture.
Step 5: Bake
- Pour the batter into the prepared pan.
- Tap the pan lightly to release large air bubbles.
- Place the cake pan into a roasting pan.
- Pour hot water into the roasting pan until it reaches halfway up the cake pan.
- Bake for 65–75 minutes.
The cake is done when:
- The top is lightly golden.
- It springs back gently when touched.
- A toothpick inserted near the center comes out mostly clean.
Step 6: Cool
- Turn off the oven.
- Leave the oven door slightly open.
- Let the cake rest inside for 20–30 minutes.
- Remove from the water bath.
- Cool completely before removing from the pan.
For the fluffiest texture, chill the cake for 2–3 hours before serving.
Tips for Success
- Use room-temperature ingredients.
- Sift the flour to avoid lumps.
- Fold the egg whites gently to keep as much air as possible.
- Do not open the oven while baking.
- Cool the cake gradually to reduce shrinking or cracking.
- Fresh sourdough discard (1–3 days old) gives the best flavor.
Storage
- Refrigerate in an airtight container for up to 3 days.
- Let it sit at room temperature for 15–20 minutes before serving.
Flavor Variations
- Lemon Cloud Cake: Add 1 tablespoon lemon zest.
- Vanilla Bean: Replace vanilla extract with vanilla bean paste.
- Chocolate: Fold in 2 tablespoons cocoa powder (reduce flour by the same amount).
- Matcha: Add 1 tablespoon matcha powder.
- Berry Swirl: Swirl raspberry or blueberry puree into the batter before baking.
Serving Suggestions
Dust with powdered sugar and serve with fresh strawberries, blueberries, whipped cream, or a drizzle of honey for an elegant dessert.
