Preheat the oven to 325° Fahrenheit and line a 9x13 inch pan with buttered parchment paper (you can use a pie pan or 8-9 inch pan for thicker bars). Make the crust by whisking together the flour, almond meal, sugar, and salt in a medium bowl, then use your hands to work the cubes of butter into the mixture until fully combined. Press the crust evenly into the bottom of the parchment-paper-lined pan, and bake for 15-20 minutes or until golden brown (don't over-bake!).

While the crust is baking, mix together the filling. Whisk together the eggs and sugar, then add in the juice and zest. You can leave out the flour here or add up to 4 Tbsp to give it a bit more stability (less goopy) - up to your texture taste!

Once the crust is done, let it cool for a few minutes, then pour the filling mixture over the crust and pop it back into the oven for another 20 minutes until the edges are just starting to brown. Cool completely before dusting with powdered sugar (optional) or digging in! You can cut these into squares, or scoop them out into bowls (this way you can eat more at once).