Ingredients

For the Cake Batter:

2 cups all-purpose flour

1 tsp baking powder

1 tsp baking soda

½ tsp salt

½ cup unsalted butter (softened)

1 cup sugar (or ¾ cup if you like it less sweet)

2 large eggs

1 tsp vanilla extract

3 medium ripe bananas (mashed)

½ cup plain yogurt or sour cream

¼ cup milk

For the Custard Layer:

2 cups whole milk

4 tbsp sugar

2 tbsp cornstarch

2 egg yolks

1 tsp vanilla extract

2 tbsp butter

Optional Toppings:

Whipped cream

Sliced bananas, Caramel drizzle

Instructions

Step 1: Make the Custard

1. In a saucepan, whisk together sugar, cornstarch, and milk.

2. Cook over medium heat, stirring constantly until it starts to thicken.

3. In a bowl, whisk egg yolks. Slowly add some of the hot milk mixture to temper them, then pour back into the saucepan.

4. Stir until thickened and smooth (do not boil).

5. Remove from heat, stir in vanilla and butter. Let cool slightly.

Step 2: Make the Banana Cake

6. Preheat oven to 350°F (175°C). Grease and flour a 9x13-inch pan (or two round pans).

7. In a bowl, mix flour, baking powder, baking soda, and salt.

8. In another bowl, beat butter and sugar until creamy. Add eggs one at a time, then vanilla.

9. Mix in mashed bananas and yogurt.

10. Slowly add dry ingredients alternately with milk. Mix until smooth.

Step 3: Assemble & Bake

Pour half of the cake batter into the pan.

Spoon custard evenly over batter.

Top with remaining batter (custard will sink slightly into the cake while baking).

Bake for 40–45 minutes, or until a toothpick inserted comes out clean.

Step 4: Serve

Let cool before slicing.

Top with whipped cream, sliced bananas, or caramel if desired.