• Place egg whites in the bowl of a stand mixer with whisk attachment and begin whisking at medium speed. Once the egg whites are frothy and no longer a liquid substance, add the granulated sugar in gradually. Whip until a soft peak forms; this will take several minutes, about 10-15. Add the extracts, zest and food coloring at this time and whisk until incorporated.
• Sieve the almond flour and powdered sugar together. Fold this into the meringue in thirds, mixing until the batter has a lava-like consistency and forms a ribbon when falling from the spatula.
• Preheat oven to 325°. Once the batter is the correct consistency, fill 1/2 the piping bag fit with the 1A tip. Pipe circle onto silpat mat. Bang pan on the counter several times to remove air bubbles. Let sit for 15 minutes. Bake for 13-14 minutes. Cool completely before removing from mat.

Lemon Buttercream:

• Beat the butter until creamy and then add in the milk until incorporated. Gradually add in the powdered sugar and continue beating. Finally, add the extracts and zest. Continue beating until combined and thick. Pipe the buttercream onto half of the shells and sandwich to combine.