Preheat oven to 350°. Combine almond paste, 1 teaspoon vanilla, and 2 egg whites in a large bowl; beat with a mixer until well blended.
Combine powdered sugar, baking powder, and salt. Add powdered sugar mixture to almond paste mixture, beating until blended. Stir in coconut.
Place remaining 2 egg whites in a medium bowl; beat with a mixer at high speed until soft peaks form using clean, dry beaters. Gradually add granulated sugar, 1 tablespoon at a time, beating until stiff peaks form. Gently fold egg white mixture into coconut mixture.
Scoop the mixture into a pastry bag fitted with a large star tip. Pipe the mixture into 2 tablespoon dollops about 2 inches apart onto a baking sheet lined with parchment paper.
Then slightly flatten each one to get a rounded shape. Try to keep the pointed edges intact as these get brown and crunchy.
Bake at 350° for 20 minutes or until firm. Cool in pan 2 to 3 minutes on a wire rack. Remove cookies from pan, garnish with optional almond slivers and cool completely on wire rack.