Preheat oven to 400°F. Coat a cookie sheet with cooking spray.
- Combine the flours, baking powder, salt, sugar, and artificial sweetener in the bowl of an electric mixer; beat on low speed to blend. Add margarine and beat on low speed until the mixture resembles cornmeal (about 1 minute).
- Add half-and-half, egg substitute or yolk, and vanilla and almond extracts all at once, then beat on low just until dough forms. Wrap dough well in plastic wrap and chill in refrigerator, if desired (it rolls out more easily if it has been in the refrigerator for a few hours).
- On a flat surface lightly coated with powdered sugar, roll the dough out to 1/8-inch thickness. Cut into desired shapes with cookie cutters. Transfer the shapes to the prepared cookie sheet. Brush the tops of the cookies with half-and-half and sprinkle with sugar crystals, if desired.
- Bake for about 8 minutes, or until delicately browned. Remove from pan. Let cool on wire rack or paper towel.