In a mixing bowl using an electric mixer, blend vegetable oil spread, Splenda Sweetener, and vanilla extract on medium speed.
Add egg, water, and vinegar and mix briefly.
Add flours, salt, and baking powder. Mix on low speed until dough is formed; do not overmix.
Divide dough in half. Pat each half into a circle and wrap in plastic wrap. Refrigerate about 1 hour.
Preheat oven to 350°F.
Remove dough from refrigerator and roll out on a floured work surface to about ¼-inch thick. Cut with cookie cutters. Place cookies on baking sheet.
Bake for 10–12 minutes or until lightly browned on the back. Cool slightly, then transfer to a wire rack to cool completely. Decorate with Sugar-Free Royal Icing if desired.
