Preheat oven to 350F. Coat an 8-inch square pan with cooking spray. Line with foil, letting edges extend over 2 sides. Coat foil with spray.

Sift flour and baking powder. Beat butter, sugar, egg and vanilla with a mixer until blended.

Turn to low speed, add flour mixture and beat just until combined. Beat in toffee bits.

Spread evenly in pan. Bake 22 minutes or until a tester comes out clean. Cool in pan on a wire rack. Remove from pan with foil and cut into 16 bars.