Preheat oven to 350°F Lingtly grease and line 8x8-inch baking dish with parchment paper, letting paper hang slightly over two sides of pan to use as handles for easy removal of squares.

BASE: Cream butter and brown sugar until combined. Add flour and beat until mixture is a soft dough. Press dough evenly into bottom of prepared pan. Bake in preheated oven for 20 minutes, or until lightly browned.

FILLING: Cream butter and brown sugar until light and fluffy. Beat in corn syrup, eggs and vanilla. Stir in flour and baking powder. Sprinkle raisins over baked pastry base. Pour filling over raisins.

Bake 25 minutes or until filling is set. Cool. Loosen edges of pastry and remove from pan. Cut into squares.