Step by step

1. 1 We begin by preparing the sponge cake base. Preheat the oven to 180º. Grease a baking tray with butter or vegetable oil and line it with baking paper, making sure it adheres well.
2. 2 Separate the egg yolks and whites. Beat the yolks with the sugar and lemon zest until they double in volume. Then beat the egg whites with a pinch of salt until stiff peaks form, and set aside.
3. 3 In a separate bowl, mix the flour and baking powder. Gradually add the sifted flour to the egg yolk mixture and mix well. Then, gently fold in the stiffly beaten egg whites using a spatula.
4. 4 Spread the dough evenly on the baking tray and bake for 10 to 15 minutes, depending on your oven. It's important that the sponge cake doesn't overcook, as it may break when you roll it up.
5. 5 Meanwhile, we prepare the filling. Separate the egg yolks and whites. Beat the yolks with the sugar until they double in volume and carefully add the mascarpone cheese while gently mixing.
6. 6 We soak the gelatin sheets. Once softened, we drain them and melt them in a couple of tablespoons of water. We add them to the mixture and beat well.
7. 7 Whisk the egg whites until stiff peaks form and gently fold them into the mascarpone mixture. It's important to do this step very carefully, otherwise the cream could become too runny and leak out when you fill the sponge cake.
8. 8 We leave the cream in the refrigerator for a minimum of 15 minutes. When the sponge cake sheet is baked, we roll it up and let it cool to room temperature.
9. 9 Once cooled, unroll it and brush it with the coffee and amaretto mixture. Then fill it with the mascarpone cream, leaving a 1-centimeter border around the edges.
10. 10 We carefully roll it up, wrap the arm in cling film and put it in the freezer for 20 to 30 minutes.
11. 11 After that time, remove the cling film, trim the edges, cover the roll with a dusting of pure cocoa powder, and decorate with mint or garden leaves. Store in the refrigerator.