Blueberry Custard Cake

By Patricia Walker

Published: December 30, 2025

Updated: December 30, 2025

Imagine a cake where tender vanilla sponge meets a rich, velvety custard and juicy blueberries that burst in your mouth. Simple yet stunning, rustic yet elegant, this Blueberry Custard Cake is every baker’s dream come true.

The custard layer is the real hero here. It’s creamy, indulgent, but just firm enough to cut neat slices. One bite, and it melts in your mouth, flooding every corner with silky richness. Don’t be surprised if you find yourself sneaking extra slices before anyone else gets a chance!

This cake was born from one of those “what if…” moments that hit me suddenly. I imagined the combination, pictured the flavors, and couldn’t wait to try it. The result? Even better than I imagined.

Here’s how it works: start with a soft vanilla sponge lightly scented with lemon, smear a generous layer of custard over it—yes, just as much custard as cake—and then scatter plump blueberries generously over the top. Bake, cool, and enjoy. Each bite delivers soft sponge, creamy custard, and bursts of blueberry magic.

What Makes This Cake Special

Vanilla sponge base: I chose my yogurt-based cake batter because it holds up beautifully under the weight of custard. My signature Vanilla Cake batter, while luxurious, would flatten under this much topping.
Custard layer: We’re talking classic French crème pâtissière. Smooth, luscious, and perfectly balanced. Not overly sweet, yet luxurious. The same custard used in Flan Pâtissier.
Blueberries: They add vibrant color, juicy bursts, and an exciting texture contrast. Cake and custard alone are wonderful, but blueberries make it unforgettable.

Ingredients

Custard Layer

Full-fat milk: Low-fat works, but full-fat gives the rich mouthfeel we love.
Egg yolks: 4, for silkiness, yellow color, and thickening.
Vanilla bean paste or extract: For deep, aromatic flavor.
Sugar: Caster or superfine preferred.
Cornflour / cornstarch: For setting the custard.
Butter: Adds richness and smooth texture.

Cake Layer

Yogurt: Keeps the cake moist and tender.
Oil: Helps the sponge remain soft.
Sugar: Superfine or regular works.
Lemon zest: Adds freshness and complements the custard.
Vanilla extract: Avoid artificial essence.
Blueberries: Fresh or frozen (don’t thaw).
Flour: All-purpose/plain.
Baking powder: Ensures even rise.
Egg: One large.
Salt: Pinch to enhance flavors.

Step-by-Step Instructions

1. Making the Custard

Custard is simpler than most people think! It’s just milk thickened with egg yolks and cornflour, finished in the oven.

Heat milk with vanilla and half the sugar until steaming (do not boil).
Whisk egg yolks with the remaining sugar, then whisk in cornflour until smooth.
Gradually pour in hot milk while whisking to temper the eggs, preventing scrambling.
Return mixture to saucepan and whisk over medium heat 2–3 minutes until thickened.
Remove from heat and stir in cold butter cubes until fully incorporated.
Pour custard into a bowl, cover with cling wrap touching the surface to avoid skin formation. Set aside.

Tip: You can make custard a day ahead. It may solidify, but a quick whisk with a handheld mixer brings it back to creamy perfection.

2. Preparing the Cake Batter

Whisk together wet ingredients: yogurt, sugar, oil, egg, vanilla, and lemon zest.
Add dry ingredients: flour, baking powder, and salt. Mix until smooth and lump-free.
Pour into a lined 8”/20cm springform pan and smooth the surface.

3. Layering the Custard and Blueberries

The layering technique helps keep a straight line between cake and custard while distributing blueberries evenly.

Spoon half the custard around the edges of the cake and spread inward.
Scatter half of the blueberries over this layer.
Mix the remaining custard with the remaining blueberries and layer on top.
Smooth the surface, gently pressing in the blueberries.

4. Baking

Bake at 180°C / 350°F (160°C fan) for 45 minutes.
Optional: 10 minutes before baking is complete, gently burst a few blueberries with a small knife for extra “burstage.”

5. Cooling and Setting

Cake is done when the custard surface is firm yet slightly wobbly underneath.
Chill in the fridge for a minimum of 12 hours to fully set the custard. This step is essential for clean slices.

Pro Tip: Slice while cold, but serve at room temperature for the creamiest custard and softest sponge.

Serving & Storing

Extra blueberries on top are optional; the cake itself is already packed with flavor.
Cut like a traditional cake and serve.
Refrigerate if necessary, but bring slices to room temperature before serving for best texture.

There you have it: a rustic, creamy, blueberry-studded custard cake that’s as delicious as it is stunning. Each bite gives soft vanilla cake, silky custard, and juicy bursts of blueberry—truly unforgettable.– Patricia Walke