1️⃣ Prepare the rolled sponge cake
Preheat the oven to 180°C (350°F).
Separate the egg whites from the yolks.
Whisk the yolks with the sugar until the mixture turns pale.
Add the sifted flour and baking powder.
Beat the egg whites to stiff peaks with a pinch of salt, then gently fold them into the mixture.
Spread the batter onto a baking sheet lined with parchment paper or a silicone mat.
Bake for 10–12 minutes: the sponge should remain pliable.
Remove it from the oven and immediately turn it out onto a damp tea towel. Gently roll it up to form the log.
2️⃣ Prepare the lemon curd
In a saucepan, whisk together the eggs, sugar, and cornstarch.
Add the lemon juice and zest.
Thicken over low heat, stirring constantly.
Remove from the heat, add the butter, and stir until smooth.
Let it cool completely—the lemon curd should be quite thick.
3️⃣ Prepare the lemon mascarpone cream
In a chilled bowl, whisk together the mascarpone, heavy cream, powdered sugar, and vanilla.
Add 1 tablespoon of lemon juice.
Whisk until stiff and silky.
4️⃣ Assembling the log
