Heat sugar and butter in a saucepan over medium heat until butter melts and mixture is smooth. Remove from heat. Place mixture in a large mixer bowl; cool slightly.
Add eggs one at a time, beating slowly after each addition. Mix until smooth. Add vanilla.
Combine flour, baking powder, and salt. Add slowly to sugar mixture, beating well. Stir in butterscotch chips. Pour into a greased and floured 13 x 9 inch pan. Bake at 350 degrees Fahrenheit for 25-30 minutes or until toothpick comes out clean.