Preheat oven to 350 degrees.
Grease and flour shell-shaped pans.
Combine eggs, sugar, vanilla, Cointreau and orange peel in large bowl.
Using the whisk of an electric mixer, beat until light in color.
In a separate bowl, mix flour and 1 c chocolate chips.
Fold the flour mixture and butter alternately into egg mixture, beginning and ending with the flour.
Pour into prepared pans.
Bake 10 to 12 minutes or until golden around edges.
Cool. Sprinkle with the powdered sugar.
Melt remaining 1/3 c chocolate chips in small bowl in the microwave oven.
Drizzle over shells.