Preheat oven to 400°F Butter a 9-inch round pan, line it with a circle of buttered parchment paper and then flour the pan.
In a medium bowl, sift together the flour, baking powder, baking soda, and salt. In a mixer, cream the butter and sugar at medium-high speed for about 2 minutes until light and fluffy. Mix in the extracts and lemon zest, then beat in the egg. Working on low speed, add 1/3 of the flour mixture, then 1/2 the buttermilk mixture, then another 1/3 of the flour, the last of the buttermilk, then the last of the flour. Mix until just combined.
Scrape the batter into the pan and smooth the top. Bake 20-25 minutes until a toothpick comes out clean. Cool in the pan for 10 minutes, then finish cooling on a rack. Cool to room temperature before frosting. If frosting the cake with mascarpone frosting, store the cake in the refrigerator.
Beat cheese and cream together until smooth and creamy and slight peaks begin to form.
Sift in the powdered sugar and zest and beat until smooth.
Mix in the vanilla extract and spread on cooled cake.
Replace almond meal with hazelnut meal (hazelnuts ground into a fine powder), use vanilla extract instead of almond, use orange zest instead of lemon, and sprinkle the batter with 3/4 cup fresh mixed berries tossed with flour before baking.