• Preheat the oven to 350°F.

For Crust:

• Mix the butter and sugar with a mixer until fluffy and creamy. Slowly add the flour while mixing on low.
• Next, slowly add it to butter until it is just mixed. Scrap dough from bowl onto a floured surface. Use your hands to gently push the dough together.
• With floured hands and press the dough into a 9 by 13 baking dish. Push the dough up a ½-inch edge on all sides. Chill for 10 minutes.
• Bake the crust for 15 minutes- the crust should be a light golden brown. Let cool the crust cool while preparing the filling.

For Filling:

• Whisk the eggs, sugar, zest, juice, and flour. The filling will be very liquidly, but will set once baked. Pour the filling into the crust. Bake for 30 minutes and the filling has set.
• Let the bars cool to room temperature. Top with powdered sugar and cut into squares or triangles.