1️⃣ Prepare the Sponge Cake:

1. Preheat the oven to 325°F (160°C). Line the bottom of a 10-inch springform pan with parchment paper, leaving the sides ungreased.
2. In a mixer, beat the eggs, sugar, and vanilla extract on high speed for about 10 minutes until the mixture is pale and foamy.
3. Gradually add the sifted flour on low speed until just combined.
4. In a separate bowl, mix 1-2 cups of the batter with the melted butter, then gently fold it back into the main batter.
5. Pour the batter into the prepared pan and bake for 45 minutes, until golden and springy. Let cool completely in the pan.

2️⃣ Make the Lemon Curd:

1. In a saucepan, whisk together the egg yolks, sugar, lemon juice, and lemon zest over medium-low heat. Stir constantly for about 10 minutes until the mixture thickens and coats the back of a spoon.
2. Remove from heat and stir in the butter until smooth. Chill the curd in the fridge until set.

3️⃣ Prepare the Lemon Mousse:

1. Whip the cream, powdered sugar, and vanilla extract to stiff peaks.
2. Gently fold half of the chilled lemon curd into the whipped cream to create the lemon mousse.

4️⃣ Construct the Cake:

1. Place the cooled sponge cake back into the springform pan. Drizzle with Limoncello for extra flavor if desired.
2. Spread the lemon mousse evenly over the sponge cake layer, smoothing it out. Refrigerate for several hours or overnight until set.
3. Once set, spread the remaining lemon curd over the mousse layer for a glossy finish.

5️⃣ Garnish with Whipped Cream and Optional Candied Lemon Peel:

1. In a bowl, whip the cream with vanilla and powdered sugar until stiff peaks form. Pipe or dollop on top of the cake for decoration.
2. If using candied lemon peel, simmer lemon peel slices in a saucepan with sugar and water for 15-20 minutes. Drain and roll in sugar, then let cool before garnishing.
3. Serving Suggestions:
4. Decorate with fresh raspberries, lemon slices, and rosemary sprigs for an extra touch of elegance.