To make this almond horn recipe, preheat oven to 350° F. Break almond paste into small pieces and place in medium-size bowl or container of food processor. Add egg whites, sugar, and almond extract, and beat with electric mixer or process until mixture is very smooth. Add flour and beat or process until blended. Spoon almond mixture into pastry bag fitted with 1/2-inch (#8) plain tip. Pipe mixture into 5-inch or 6-inch crescents on prepared baking sheets about 11/2 inches apart. Sprinkle with sliced almonds. Bake 13 to 15 minutes or until edges are golden. Cool on baking sheets on wire racks 2 minutes. Remove from baking sheets and cool completely on racks. Dip ends of cookies in melted chocolate and place on sheet of aluminum foil. Let the almond horns stand until chocolate is set.