In a blender or food processor, whirl 1/2 cup of the almonds until finely ground. Set aside. Combine cream, sugar and butter in a medium-size pan and cook over low heat, stirring occasionally, until butter is melted. Increase heat to medium-high and bring mixture to a boil; then remove from heat and stir in ground almonds, remaining 1/2 cup sliced almonds, orange peel and flour; mix well. Batter will be very thin. Drop batter by level tablespoonfuls onto lightly greased and flour-dusted baking sheets, spacing cookies 3-inches apart; then spread each into a 2-inch circle with the back of a spoon. Preheat oven to 350. Bake for 10-12 minutes or until edges are lightly browned (centers will still be bubbling). Let cool on baking sheets for 1 to 2 minutes, then carefully transfer to racks with a wide spatula and let cool completely. Turn cooled cookies upside down on a piece of wax paper. Place chocolate and shortening in top of a double boiler over simmering water (or use microwave); stir until melted. With a soft pastry brush, paint a thin layer of chocolate over bottom of each cookie. Refrigerate until chocolate has hardened; the cover lightly and store in the refrigerator for up to 3 days.