Butterscotch Brownies

1/4 cup butter
1 cup brown sugar
1 egg
1 1/2 teaspoon vanilla
1/2 cup flour
1 teaspoon baking powder
optional: 1 cup chopped almonds, walnuts, or pecans

Melt the butter. Add the brown sugar and stir well to dissolve. If needed, heat the mixture slightly to aid the dissolving. Let cool for a few minutes. Stir in the egg and vanilla. Add the flour and baking powder. Stir to combine. Add the nuts. Pour into a greased cake pan. Bake 20-25 minutes at 350 degrees.