With electric mixer, combine almond paste, sugar, confectioner's sugar, cocoa and egg whites.  Mix on low speed until blended, then mix for 2 minutes on medium speed.  Dough will be sticky.

Roll dough into 1" balls. (Moistening your palms with water helps to keep the dough from sticking to your hands.  Or...just use a small cookie scoop).  Roll the cookies in a bowl of sliced almonds and place on a parchment-lined cookie sheet.  Slightly flatten the tops of the cookies.  Bake at 350 degrees for 15 - 20 minutes.  Leaving the cookies on the parchment paper, cool completely on rack.  Remove with spatula.