Preheat oven to 180 degrees. Grease and flour an 8 inch pan and set aside.
Combine all ingredients for the butterscotch sauce and cook on low flame till all melted and combined.
Beat butter and sugar till soft and fluffy. Add the egg and vanilla and beat till combined. Scrap down the sides and beat.
Whisk together the dry ingredients in a bowl.
Add half the dry ingredients and half the milk to the butter mixture, beat till done.
Add the remaining and beat ill combined.
Spread the batter in the prepared pan. Pour the hot sauce on top.
Bake for 30 minutes or till a skewer inserted comes out clean. Cool in pan for 10 minutes.
Serve warm with a scoop of ice cream.