Mix the flour and salt and add to the butter until just mixed and it looks crumbly. Use a stand mixer or a spoon.
Gather the dough into a ball.
Place the dough into a 9 by 13 by 2-inch baking sheet, and flatten it all the way to the sides. You should build up the edges to about half an inch on all sides
Chill the flattened dough along with the baking sheet for about 15 minutes.
Then bake the crust for 15 minutes, until very lightly browned. Let cool on a wire rack and do not remove it from the pan. not yet.
Make the Filling -
Whisk the eggs with sugar, lemon zest, lemon juice, and flour.
Pour this mixture over the baked crust and bake for 35 minutes. Check on it at 30 minutes mark and see if the filling looks set.
Once the filling is set, remove and let it cool completely before cutting.
Cut into desired shape and dust with powdered sugar.
Recipe Notes
If you don't have one big pan, cut the recipe in half and bake in an 8 in square pan or a 9 or 10 in round or use two smaller pans and use the whole recipe.