Preheat oven to 350 degrees. In medium size bowl, combine
flour, powdered sugar and margarine; blend until crumbly.
Press flour mixture into 8x8-inch baking pan, making a level
crust. Bake for 20 minutes, remove from oven. In a mixing
bowl, combine eggs, sugar, baking powder, salt and lemon
juice; mix well. Pour lemon mixture over crust, bake for 20
to 25 minutes or until filling is set. Let cool for 30 minutes
before cutting into squares.