Blend flour, butter and powdered sugar together.
Press lightly into bottom of (8 x 8-inch) baking dish.
MICRO WAVE 3 MINUTES on HIGH, or until firm.
Beat eggs until light.
Stir in flour, baking powder, granulated sugar, lemon rind and juice.
Pour over baked layer.
MICROWAVE 6 MINUTES on HIGH, or until top is set and custard like.