Polvorones (Mexican Wedding Cakes)

Preheat oven to 400^F.

In a large bowl, beat shortening and butter until fluffy.

Add sugar a little bit at a time.

Add egg yolks, orange juice, and peel.

Stir in flour with spatula.

On a floured surface, roll out the dough to 3/4". Cut out 2 1/2" circles and place them on a greased baking sheet. Roll the dough scraps and continue to roll until all the dough is used.

Bake for 25 minutes. Be careful not to overcook them--they are done when they are barely starting to tan.

Transfer to a rack to cool.

Sprinkle with powdered sugar through a fine sieve.