Pre-heat oven to 350F. Grease and flour two 9-inch rounc cake pans. beat and mix cake mix, buttermilk, oil, eggs, orange and vanilla extract and grated peel until throughly mixed. Fold in 1 -1/2 cups chocolate chips. Pour into pans. Bake 30-35 minutes or until a wooden tooth pick inserted in the center of cake comes out clean. Remove from pans and cool on wire racks.
To prepare frosting - beat butter and marshmallow fluff until creamy. Add confectioners sugar, vanilla extract, orange extract and orange peel and beat until smooth.
place one cake layer on cake plate and frost completely. Top with other cake and frost completely. Spread remaining frosting on sides of cakes to blend the cakes together as one. Sprinkle cake with remaining 1/2 cup of chocolate chips.