In a food processor (or by hand) pulse flour, sugar, and butter (cubed) until combined. The mixture will resemble coarse crumbs.
Press firmly into a 8'' x 8'' baking dish.
Bake at 325 for 20 minutes.
In a medium sized mixing bowl, combine sugar, beaten eggs, lemon zest, juice, flour, b. powder, and salt with a whisk until well combined.
Pour over hot shortbread.
Bake at 325 for 25 minutes.
Let cool completely before cutting into squares. Enjoy!