Combine flour and icing sugar; cut in butter until crumbly. Press onto bottom of greased 13 x 9" pan. Bake at 350 F for 15 to 18 minutes. In saucepan, melt jam over low heat; spread on baked crust. In large bowl, combine granulated sugar, flour and baking powder. Add eggs, lemon juice; mix well. Carefully pour lemon mixture over raspberry layer. Bake 20 to 25 minutes or until golden brown. Cool. Spread with glaze and let set. Cut into bars. Makes 30 bars.