Work together almond paste and sugar on a smooth board or marble slab. Then add whites of eggs gradually, and work until mixture is perfectly smooth. Confectioners at first use the hand, afterward a palette knife, which is not only of use for mixing but for keeping board clean. Shape, using a pastry bag and tube, on a tin sheet covered with buttered paper, one-half inch apart; or drop mixture from tip of spoon in small piles. Macaroon mixture is stiff enough to hold its shape, but in baking spreads. Bake fifteen to twenty minutes in a slow oven. If liked soft, they should be slightly baked. After removing from oven, invert paper, and wet with a cloth wrung out of cold water, when macaroons will easily slip off.