Mix together the melted butter and sugar.
Add the egg and vanilla.
Mix together flour, baking powder, baking soda and salt.
Mix wet ingredients with dry ingredients.
Add the butterscotch chips.
Pour into a greased and floured 8X8 inch pan, spreading evenly.
Bake in a preheated 350 degree oven for 20 to 25 minutes or until a toothpick comes out clean.
Allow to cool completely before cutting into squares.