For the cake (Adapted from Baran Bakery):

1. Preheat the oven to 350 fahrenheit and line the bottom of two 9 inch round pans with parchment paper.
2. In a large bowl or the bowl of a stand mixer, beat together the egg whites and granulated sugar for a few minutes at full speed, until the mixture holds stiff peaks.
3. Next, add the egg yolks, melted butter and vanilla extract and beat at medium speed, just until they’re combined.
4. Sift the flour and salt over the batter and turn the mixer up to medium speed. Once again, do not overbeat, just until ingredients are incorporated.
5. Scrape the edge of the bowl and distribute batter evenly between the prepared pans and bake for about 20 minutes. The tops should be golden brown and spring back when you gently press on the center.
6. Remove the cakes from the oven and run a knife around the edge of the cake to release it from the pan. Allow it to cool for 15 minutes in the pan and then remove the cakes and place them onto a cooling rack.
7. Once the cakes are completely cool, use a sharp serrated knife to remove a very thin layer off the tops of the cakes. This will allow the limoncello syrup to soak into the cake more.

For layer cake assembly:

1. Once you have made all of the ingredients in the recipes below to put on top of the cakes, come back to this step.
2. First, brush the tops of both cakes with limoncello syrup.
3. Mix the vanilla pastry cream, the lemon cream, and the whipped cream together in a bowl. (See below for individual recipes).
4. Place one cake on a parchment lined cake plate and spread a thick layer of the cream on top of the first cake.
5. Next gently place the second cake on top, making certain the cream does not come out the sides.
6. Frost with the limoncello frosting, reserving a bit of frosting to fix any smudges before serving.
7. Cover and chill in the refrigerator if not served immediately. Decorate as desired with candied lemon, fresh lemon slices, and or flowers.

For the lemon cream:

1. In a small pan heat lemon juice and lemon peel over medium heat.
2. In a separate bowl, thoroughly mix the egg yolk, sugar, and vanilla extract.
3. Once the lemon juice is very warm (not too hot), slowly pour it into the egg yolk bowl while whisking.
4. Once fully mixed, pour it all back into the pan and cook until 175 degrees fahrenheit. Note: Make sure to use a thermometer on the cream to not exceed 175 degrees, as it may cause the cream to curdle.
5. As soon as the cream hits 175 degrees, remove the pot from the heat, and pour the cream into the bowl (without the lemon peel).
6. Let the cream cool to about 105 degrees.
7. Add the softened butter and stir together until well incorporated.
8. Cover and place in the fridge until ready to assemble.

For the vanilla pastry cream:

• 2 cups whole milk
• 1 lemon peel
• 1 egg (room temperature)
• 2 egg yolks (room temperature)
• ½ cup granulated sugar
• 3 tbsp cornstarch (sifted)
• 2 tbsp butter (room temperature)

For the pastry cream:

1. In a medium-heavy saucepan, over medium heat, combine the milk and lemon peel.
2. Heat the milk until it starts to steam, but do not let it boil.  Remove from the heat and let cool for at least 10 minutes allowing the lemon peel to infuse the milk.
3. While the milk is heating, whisk eggs with the sugar.
4. In a small bowl, sift the flour and salt together. Add these dry ingredients to the egg mixture, whisking continuously for about 5 minutes or until mixture lightens in color.
5. Remove the lemon peel from the milk. Then slowly add one ladle of the hot milk to the egg mixture, whisking continuously. Gradually add all the hot milk while whisking.
6. Pour the mixture back into the saucepan and over medium heat, whisk continuously for about 5 minutes or until it thickens. Be careful to not let it boil.
7. Once it has thickened, take the saucepan off the heat and let cool for a few minutes.
8. Finally, add two tablespoons of butter cut into pieces and whisk together
9. Place the mixture into a ceramic or glass dish, covered with a piece of plastic wrap, making sure it is in direct contact with the pastry cream. This keeps a skin from forming on top of the cream.
10. Allow to cool for at least 15 minutes, then place in a refrigerator until ready to use. Make sure to use it within 3 days.

For the limoncello syrup (adapted from pasta.com):

1. Heat water, sugar, and the lemon peel in a small pot over medium low heat, stirring to dissolve the sugar.
2. Once the sugar has fully dissolved, remove the pot from the heat and add in the Limoncello.
3. Cover and let it infuse at room temperature for at least an hour, then strain.

For the whipped cream:

1. In a large bowl (preferably metal), stir sugar into room temperature heavy cream until completely dissolved.
2. Place both lemon peels into the heavy cream. Cover and place the bowl in the fridge to infuse overnight (12 hours). If time does not allow for this, simply add 1 tsp of lemon extract, cover, refrigerate until completely chilled, then whip until whipped cream consistency.
3. If infusing the cream overnight, remove lemon peels and whip the lemon cream until it thickens and soft peaks form (about 3-5 minutes.)

For the condensed milk limoncello buttercream: 

1. Place the butter into the bowl of a stand mixer or other large bowl, if using a hand mixer.
2. Beat for at least 5 minutes until butter is very whipped and lightens in color. At this stage, sprinkle in the salt, add the lemon extract and pour in the condensed milk gradually as you continue whipping on low speed until a creamy smooth consistency is reached.
3. Slowly add in the limoncello 1 tablespoon at a time while continuing to whip on low speed. Taste and adjust flavors.