Preheat oven to 350 degrees F. Grease a cookie sheet and set aside.
Blend together the butters, SPLENDA® Granulated Sweetener and vanilla in a medium mixing bowl with an electric mixer, or by hand until completely combined. Then add in egg substitute, water and vinegar. Mix a little more and then add flours, salt and baking powder. Mix on low speed, until dough is formed. Do not overmix.
Place dough on a lightly floured work surface and divide into two balls. Pat each half into a thick disc and cover with plastic wrap. Chill dough
After chilling, roll out dough on a floured work surface to about 1/4 inch. Cut with your cookie cutter of choice and then place on the prepared baking sheet.
Bake cookies for 10-12 minutes or until very lightly browned on the back. Allow cookies to cool before decorating.