In a large bowl, cream together the shortening, butter, and sugar with an electric mixer until fluffy. Add egg, vanilla, orange juice, and red food coloring. Mix until well blended. Sift together the flour, baking powder, and salt. Stir into butter mixture until blended. Chill dough in refrigerator for three hours.

Preheat oven to 375 degrees F (190 degrees C).

On a floured surface, roll out the dough to 1/4 inch thickness. Cut with a three inch round cookie cutter. Cut cookies in half and place on an ungreased cookie sheet. Press a few chocolate chips into each cookie. Bake in preheated oven for 8 to 10 minutes. Do not brown. Remove from baking sheet and cool on a wire rack.

In a small shallow bowl, stir together the egg white and water. Brush the round edge of each cookie with the liquid and roll it in the green sugar. Let cookies dry on wire cooling racks.