Preheat the oven to 350°F. Lightly butter and flour an 8X8 pan.
Whisk together the melted butter and sugar in a bowl.
Add the egg and vanilla extract and whisk.
Add the flour, baking soda, baking powder, and salt, mix it all together.
Add the butterscotch chips or other mix-ins.
Pour into the pan and spread evenly.
Bake for 20-25 minutes or until a toothpick comes out clean. Allow to cool. Cut into squares and serve. Yield: Makes 9 blondies.