Heat oven to 350°F. Grease 13x9-inch pan with shortening. In large bowl with electric mixer, beat granulated sugar, brown sugar and butter on medium speed until well blended. Beat in vanilla and eggs until light and fluffy. On low speed, beat in flour, baking powder and salt until dough forms. With spoon, stir in 1/2 cup toffee bits. Spread in pan.