Sweet potato brownies

Source: Wheat Food Council1/2 cup margarine1 cup granulated sugar1/2 cup Splenda5 egg whites1/2 tablespoon vanilla extract3/4 cup all-purpose flour1/2 cup oatmeal1/2 cup baking cocoa1/2 teaspoon baking powder1 cup cooked sweet potato, without skin, mashed1/4 cup chopped pecansPreheat oven to 350 degrees F. Lightly grease a 9 x 12-inch baking pan.Cream the margarine and sugar. Add the egg whites one at a time, beating after each addition. Scrape the bowl well. Add remaining ingredients except the pecans. Mix well. Spread batter in pan. Top with pecans and bake until the brownies are firm in the center, about 30 minutes.