Melt the butter in a medium glass mixing bowl in the microwave.
Add the sugar and mix well.
Add the egg and vanilla, stirring until mixed.
Add the flour, baking powder, soda, and salt. Mix until just blended.
Pour into a sprayed 9" x 9" x 2" pan.
Sprinkle chocolate chips over the top.
Bake at 350 degrees for 25 minutes.
Cut into 16 squares.
