Sweet Potato Biscuits

1 cup all-purpose flour
1/2 teaspoon salt
3 teaspoons baking powder
4 tablespoons solid shortening
1 cup cooked sweet potatoes, mashed
1/2 cup milk

Sift dry ingredients together. Cut in shortening. Add mashed potatoes. Add enough milk to make firm dough but not too stiff. Roll out on floured board, then cut with biscuit cutter. Place in a greased biscuit pan and bake for 25 to 30 minutes at 400 degrees until browned.