Preheat your oven to 180°C (350°F) and line the baking tray with parchment paper.

In a mixing bowl, whisk together the eggs and granulated sugar until pale and fluffy, about 5 minutes using an electric mixer.

Sift the flour, baking powder, and salt into the egg mixture. Gently fold the dry ingredients into the wet mixture using a rubber spatula, making sure to keep the air in the batter.

Pour the batter into the prepared baking tray and smooth it out evenly. Bake for 15 minutes or until lightly golden and a skewer comes out clean.

While the cake is baking, prepare the filling. In a bowl, combine mashed bananas, mascarpone cheese, powdered sugar, and lemon juice. Mix well and set aside.

For the caramel sauce, combine sugar and water in a saucepan over medium heat. Cook without stirring until the sugar dissolves and turns a golden caramel color. Gradually whisk in the heavy cream and cook for another 2 minutes. Add butter and salt, then remove from heat.

Once the cake is done, remove it from the oven. Place a clean kitchen towel on the counter and sprinkle it with powdered sugar. Carefully flip the cake onto the towel and gently peel off the parchment paper.

Spread the banana filling evenly over the warm cake, then roll it up tightly with the towel starting from the short end. Wrap it in plastic wrap and chill in the refrigerator for at least 30 minutes.

When ready to serve, unroll the roulade and slice it into pieces. Drizzle with warm caramel sauce and enjoy!