1. Preheat your oven to 350°F (175°C). Line a jelly roll pan with parchment paper.
2. In a mixing bowl, beat the egg yolks with 1/2 cup of sugar until the mixture becomes light. Stir in the mashed bananas and vanilla.
3. In another bowl, whisk the egg whites until soft peaks form. Gradually add 1/4 cup of sugar while whisking until stiff peaks form.
4. Sift together the flour, baking powder, and salt. Fold this mixture into the yolk mixture, then gently fold in the beaten egg whites.
5. Spread the batter evenly onto the prepared pan. Bake for 12-15 minutes.
6. Once baked, immediately turn the sponge out onto a clean towel dusted with powdered sugar. Roll up the sponge and towel together, then let it cool completely.
7. For the filling, beat the heavy cream with powdered sugar and vanilla until stiff peaks form.
8. Unroll the sponge and spread the whipped cream evenly over it. Arrange the sliced bananas on top. Carefully re-roll the cake without the towel.
9. To make the caramel sauce, combine the brown sugar, cream, butter, vanilla, and salt in a saucepan over medium heat. Bring the mixture to a boil while stirring constantly until it thickens.
10. Drizzle the caramel sauce over the rolled cake. Sprinkle with crushed graham crackers and banana slices. Dust with powdered sugar for the finishing touch.
Prep Time: 30 minutes | Cooking Time: 15 minutes | Total Time: 45 minutes | Calories: 450 kcal | Servings: 10 slices
