In a mixing bowl, stir together the graham cracker crumbs, melted butter and sugar until well mixed. Line a 9x13 glass baking dish with parchment paper, then press the graham cracker mixture into the bottom of a pan using your hands or a spatula to firmly pack the crust into the pan. Bake the crust for 8-10 minutes until it starts to darken, then remove from the oven.
While the crust bakes, zest the lemons, then cut them in half and press the juice out of them.
Whisk together the eggs, sugar, lemon zest, lemon juice, and flour. Pour the lemon egg mixture over the crust and bake for 30 to 35 minutes, or about five minutes beyond the point where the filling is set.
Let the bars cool to room temperature, then refrigerate until cold. Then, cut the bars into small squares and dust them with powdered sugar before serving.
Notes
Hint: It's not necessary to line the baking dish with parchment paper, but it makes it much easier to remove the cooked bars from the pan. If not using parchment paper, be sure to grease the pan before pressing in your crust.Always opt for a glass baking pan when preparing these bars. Glass pans distribute heat more evenly, resulting in a perfectly baked graham cracker crust and a smooth, luscious lemon filling. The transparency of the glass also allows you to monitor the browning process, ensuring that your bars achieve the ideal golden hue without overcooking. Plus, the non-reactive nature of glass minimizes the risk of any metallic taste from using a metal pan.