Banana Muffins

1 1/3 cups flour

1/2 cup splenda

1 tsp. baking powder

1/2 tsp. baking soda

1  pinch salt

1 tlbs. oil

1/3 cup buttermilk

2 tsp. vanilla

1 1/4 cup mashed banana

1/4 cup walnuts

Bake at 350 degrees for 45-55 min.