Heat oven to 375°F. Spray 8-inch square pan with nonstick cooking spray. In medium bowl, combine brown sugar and margarine; beat well. Add egg product and vanilla; blend well. Add flour and baking powder; stir just until dry ingredients are moistened. Spread in sprayed pan. Sprinkle evenly with chips.
Bake at 375°F. for 20 to 25 minutes or until brownies are golden brown and toothpick inserted in center comes out clean. Cool at least 30 minutes or until completely cooled. If desired, sprinkle with powdered sugar. Cut into bars.