Step 1: Preheat your oven to 180°C (350°F). Peel and slice the bananas into even rounds, about 1/2 inch thick.
Step 2: In a non-stick skillet over medium heat, melt 50 grams of butter. Add 100 grams of sugar and stir until smooth caramel forms. Add banana slices and cook for 2-3 minutes. Transfer to a greased 9-inch round cake pan.
Step 3: In a mixing bowl, whisk together flour, baking powder, and salt. In another bowl, beat the softened butter and remaining sugar until light and fluffy. Add egg yolks one at a time, mixing well. Stir in vanilla.
Step 4: Gradually add dry ingredients to the butter mixture, alternating with milk, starting and ending with flour. Mix until just combined.
Step 5: In a separate bowl, whisk egg whites with cream of tartar until stiff peaks form. Gently fold into the cake batter.
Step 6: Pour the batter over the caramelized bananas in the cake pan. Bake for 30-35 minutes or until a toothpick comes out clean. Allow to cool for 10 minutes.
Step 7: Carefully flip the cake onto a serving platter. Serve warm with whipped cream or vanilla ice cream.
Notes
For best flavor, use ripe bananas. Ensure egg whites are at room temperature for easier whipping.