Step 1In a mixing bowl, combine the flour, almond flour, coconut and salt. Set aside.
Step 2In another bowl, cream together the butter and sugar until light and fluffy. Add the egg and egg yolk separately until each is fully incorporated. Add the flour mixture, one-third at a time, and stir until incorporated in the dough.
Step 3Spread a large sheet of plastic wrap on the work surface, place the soft dough on the plastic and pat it into a rectangle. Wrap the dough tightly with the plastic wrap and refrigerate until firm, 2 to 3 hours.
Step 4Heat the oven to 350 degrees. Roll half the dough (keeping the other half wrapped and refrigerated), between two lightly floured sheets of parchment paper, to one-fourth-inch thickness. Remove the top sheet and cut out the cookies using a 2-inch round cutter. Remove the cookies from the bottom sheet and place them, spaced 1 inch apart, on baking sheets lined with lightly oiled parchment paper or a Silpat. Repeat with the remaining dough. Freeze the sheets until the cookies are solid, 45 minutes to 1 hour.
Step 5Remove the cookies from the freezer and bake about 15 to 20 minutes, until golden. Cool on a rack.