Place the oven rack in the middle and preheat oven to 300° F/150° C.
In the bowl of the stand mixer on medium speed(or the food processor or in a bowl with a wooden spoon), work the almond paste until it’s smooth. Add the egg whites and blend thoroughly. The mixture will look a little soupy at first, but will come together.
In the small bowl, sift together the sifted pastry flour, granulated sugar, and powdered sugar. Add to the almond paste mixture in thirds and mix just until combined.
Drop the cookies by the teaspoonful onto the lined baking sheet. Bake for about 30 minutes. Remove from the oven and allow to rest on baking sheet for a couple minutes, then transfer to a wire rack. Allow to cool completely, then store in a tin in a cool dry place. Tastes best after they sit for a couple days, and will keep for several months.
Add finely chopped or ground fruits when mixing.
Shape cookies with a cookie press or with a pastry bag and tip.
Decorate by placing half a nut or a raisin on top of each cookie before baking.