Mix together margarine, flour, sugars and salt.
Grease a pan and press dough evenly into the bottom and about
1/2 inch up the sides, making sure there are no cracks.
Bake at 350 F for about 25 minutes, until crust is golden.
For the filling, whisk together eggs, sugar, lemon zest, lemon
juice, and flour.
Once the crust has cooled, pour over the crust and bake for 30-
35 minutes until the filling is set.
Let cool to room temperature.
Dust with confectioners sugar and keep in refrigerator.