In a small bowl, beat almond paste and sugar until crumbly. Beat in 2 egg whites. Gradually add confectioners' sugar; mix well., Whisk remaining egg whites in a shallow bowl. Place pine nuts in another shallow bowl. Shape dough into 1-in. balls. Roll in egg whites and coat with pine nuts. Place 2 in. apart on parchment-lined baking sheets. Flatten slightly., Bake at 325° until lightly browned, 15-18 minutes. Cool for 1 minute before removing from pans to wire racks. Store in an airtight container.