Baked Custard Butter Cake Squares 🍰🥛

These Baked Custard Butter Cake Squares combine a rich, buttery cake with a silky custard-like center. The top becomes lightly golden while the middle stays soft, creamy, and delicate. It’s an easy old-fashioned dessert that’s wonderful with tea or coffee.

Ingredients

For the Cake Batter

1 cup (225 g) unsalted butter, softened
1 cup (200 g) granulated sugar
4 large eggs, room temperature
1 teaspoon vanilla extract
1½ cups (190 g) all-purpose flour
1½ teaspoons baking powder
¼ teaspoon salt
½ cup (120 ml) whole milk

For the Custard Layer

2 cups (480 ml) whole milk
½ cup (100 g) granulated sugar
3 large egg yolks
3 tablespoons cornstarch
1 teaspoon vanilla extract
2 tablespoons unsalted butter
Pinch of salt

For Finishing

Powdered sugar
Fresh berries, optional

Directions

1. Prepare the Pan

Preheat your oven to 350°F (175°C).

Grease a 9×13-inch baking pan and line it with parchment paper, leaving some overhang on the sides.

This will make the finished squares easier to remove.

2. Make the Custard

Pour the milk into a medium saucepan.

In a separate bowl, whisk together the sugar, egg yolks, and cornstarch until smooth.

Slowly whisk about ½ cup of the cold milk into the egg mixture.

Pour this mixture back into the saucepan with the remaining milk.

Place over medium-low heat.

Cook while whisking constantly until the mixture thickens to a smooth custard consistency, approximately 5–8 minutes.

Don’t allow it to boil aggressively.

Remove from the heat.

Stir in the vanilla, butter, and salt.

Transfer the custard to a bowl.

Cover the surface directly with plastic wrap to prevent a skin from forming.

Allow it to cool until warm, not hot.

3. Make the Butter Cake Batter

Place the softened butter and sugar in a large bowl.

Beat for approximately 3–4 minutes, until light and fluffy.

Add the eggs one at a time, beating well after each addition.

Mix in the vanilla.

In a separate bowl, whisk together:

Flour
Baking powder
Salt

Add the dry ingredients to the butter mixture in two or three additions, alternating with the milk.

Mix only until combined.

Don’t overmix the batter.

4. Assemble the Cake

Spread approximately two-thirds of the cake batter into the prepared pan.

Use a spatula to create an even layer.

Carefully spoon the cooled custard over the cake batter.

Spread it gently, leaving a small border around the edges.

Dollop the remaining cake batter over the custard.

Don’t worry if the custard isn’t completely covered—the batter will spread as it bakes.

5. Bake

Place the pan in the preheated oven.

Bake for approximately 35–45 minutes, or until:

The top is golden brown.
The cake feels set around the edges.
A toothpick inserted into the cake portion comes out mostly clean.

The custard layer should remain soft and creamy.

Don’t overbake, or the custard can become dry.

6. Cool Completely

Remove the cake from the oven and place it on a cooling rack.

Allow it to cool completely in the pan.

For the cleanest slices, refrigerate it for 1–2 hours after cooling.

7. Cut Into Squares

Lift the cake from the pan using the parchment paper.

Dust generously with powdered sugar.

Cut into squares using a sharp knife.

For cleaner cuts, wipe the knife between slices.

Serve chilled or slightly cool.

Dos and Don’ts

Do ✅

Do use room-temperature eggs and softened butter.
Do whisk the custard constantly while cooking.
Do cool the custard before assembling the cake.
Do mix the cake batter gently.
Do bake at moderate heat.
Do cool completely before cutting.
Do refrigerate for cleaner, neater squares.

Don’t ❌

Don’t boil the custard aggressively.
Don’t add hot custard directly to the cake batter.
Don’t overmix the cake batter.
Don’t overbake the cake.
Don’t cut it while it’s still hot.
Don’t skip the parchment paper if you want easy removal.

Tips for Perfect Custard Cake Squares

For an Extra Creamy Custard

Replace ½ cup of the milk with ½ cup heavy cream.

Add Lemon Flavor

Add 1 teaspoon finely grated lemon zest to the custard for a bright flavor.

Add Almond Flavor

Replace half the vanilla extract with ½ teaspoon almond extract and sprinkle sliced almonds over the top before baking.

Make It More Decadent

Drizzle the cooled squares with melted white chocolate or serve with a spoonful of whipped cream.

For a Golden Top

Brush the exposed cake batter lightly with melted butter before baking.

Storage

Because of the custard filling, store these cake squares covered in the refrigerator.

They are best enjoyed within 3–4 days.

Allow them to sit at room temperature for about 10 minutes before serving if you prefer a softer texture.

Meta Description

These Baked Custard Butter Cake Squares feature a rich buttery cake layered with creamy vanilla custard and finished with powdered sugar. An easy, comforting homemade dessert.