Ingredients:
- 115g unsalted butter, softened
- 150g granulated sugar
- 2 large eggs, room temperature
- 5ml vanilla extract
- 225g over-ripe mashed bananas
- 250g all-purpose flour
- 5g baking soda
- 3g salt
- 120ml sour cream
- 240ml heavy cream
- 25g cornstarch
- 50g granulated sugar
- 115g mashed banana, strained
- 15g unsalted butter
- 225g full-fat cream cheese, softened
- 115g unsalted butter, softened
- 360g powdered sugar
- 5ml lemon juice
- 1g salt
Instructions:
- Beat 115g softened butter and 150g sugar until pale and fluffy (about 3 minutes). Add eggs one at a time, then stir in vanilla and 225g mashed bananas.
- Sift flour, baking soda, and salt together. Gently fold into the wet mixture, alternating with the sour cream.
- Pour batter into two lined 8-inch round cake pans and bake at 350°F (175°C) until a toothpick inserted in the center comes out clean.
- In a saucepan, combine 50g sugar and 25g cornstarch; slowly whisk in 240ml heavy cream.
- Heat over medium, stirring constantly until the mixture thickens and coats the back of a spoon.
- Remove from heat and whisk in strained mashed banana and 15g butter until glossy and smooth. Chill completely.
- Cream 225g softened cream cheese and 115g softened butter until no lumps remain.
- Slowly add 360g powdered sugar on low speed, then increase speed and stir in lemon juice and a pinch of salt.
- Assemble the cake by layering sponge, banana custard, and frosting. Chill for 4 hours for structural stability before slicing.