Step 1: Dough In a stand mixer fitted with the paddle attachment, mix together the butter and sugar until soft and airy. Add the egg yolks, egg, and lemon oil and mix until incorporated. In a small bowl, whisk together the baking powder, salt, and flour and slowly add into the butter mixture. Add the almond flour and mix until fully incorporated. Remove the dough and form into two flat disks. Wrap in plastic and refrigerate at least 2 hours, or overnight.