Prepare brownie batter according to package directions, using 3 eggs.
Place the ice cream cones in muffin cups; spoon about 3 tablespoons batter into each cone.
Bake at 350° for 25-30 minutes or until a toothpick comes out clean and tops are dry (do not overbake). Cool completely.
In a microwave, melt chocolate chips and shortening; stir until smooth. Dip tops of brownies in melted chocolate; allow excess to drip off. Decorate with sprinkles.