Lemon Layer Cake with Vanilla Bean Frosting

For the cake:

cake flour

baking powder

salt

unsalted butter, at room temperature

Zest of ½ a lemon

sugar

large eggs, at room temperature

buttermilk, at room temperature

lemon extract

vanilla extract

For the filling:

mascarpone or cream cheese, cold

unsalted butter, at room temperature

confectioners’ sugar, sifted

lemon extract

Zest of ½ a lemon

heavy cream, chilled

For the frosting:*

plus 2 tbsp. (3 sticks plus 2 tbsp.) unsalted butter, at room temperature

confectioners’ sugar, sifted

salt

vanilla bean, split lengthwise

vanilla extract

heavy cream

For the candied lemon slices:

whole lemons, preferably organic

sugar

water

*Note: This will make a bit more frosting than you need for the cake.  You can scale it down a bit or just have left over frosting…always a good thing in my book.