Preheat your oven to 375°F (190°C). Line the jelly roll pan with parchment paper and lightly grease it.

In a mixing bowl, whisk the eggs and granulated sugar together until the mixture is pale and has doubled in volume. Add the vanilla extract and mix well.

Sift the flour, baking powder, and salt together. Gently fold this dry mixture into the egg mixture using a rubber spatula, being careful not to deflate the batter.

Pour the batter into the prepared pan, spreading it evenly. Bake in the preheated oven for about 12-15 minutes, or until the cake springs back when lightly touched.

While the cake is baking, prepare the filling. In a saucepan, blend the mashed bananas and caramel sauce, and bring to a gentle simmer. Remove from heat and let cool.

In a separate bowl, whip the heavy cream until soft peaks form. Add powdered sugar and vanilla extract and continue whipping until stiff peaks form. Gently fold the whipped cream into the cooled banana caramel mixture until well combined.

Once the cake is ready, remove it from the oven and let it cool for a few minutes. Turn the cake out onto a clean kitchen towel dusted with powdered sugar, and carefully peel off the parchment paper.

Spread the banana caramel filling evenly over the cake. Starting from one edge, roll the cake tightly with the towel to form a roulade. Place seam-side down on a serving platter and refrigerate for at least 30 minutes to set.

Before serving, dust the roulade with additional powdered sugar and slice into rounds.