Make the graham cracker crust:Preheat the oven to 400° and spray a 13 x 9 baking dish with cooking spray. Line the center of the dish with parchment paper. cutting a piece large enough to let the paper hang over the sides of the baking dish. This creates a sling and makes getting the bars out of the pan easier! Spray the parchment with cooking spray too.

Break your graham crackers into big pieces and put them in the bowl of a food processor. Add the sugar and pinch of salt. Process the ingredients until only a few big lumps of graham cracker remain.

Pour in the melted butter and pulse until the crumbs are crushed fine and evenly moistened. They should clump together slightly.

Pour the crumbs into the prepared baking dish and use the bottom of a glass to press the crumbs into an even and compact layer.

Pop the baking dish in the freezer and for 10 minutes to firm up. *This is optional if you don't have the freezer space, but it helps keep the crumbs in place when we brush on the egg wash later.

Once the cracker mixture has firmed up, pour the beaten egg over the crust and use a pastry brush to distribute the egg wash evenly over the surface.

Pop the baking dish in the oven and bake the crust at 400° for 12-15 minutes until the outer edges of the crust begin to brown.

Make the lemon fillingWhile the graham cracker crust is baking, combine the sugar, lemon zest, lemon juice, eggs, and flour in the bowl of a blender or food processor. Add the flour last to prevent clumping. Blend until smooth, about 20-30 seconds.

Once the crust is baked, remove it from the oven and turn the temperature down to 350°.

Pour the lemon mixture over the hot graham cracker crust.

Pop the baking dish back into the 350° oven and bake for 30-35 minutes.

The lemon bars are done when the center barely jiggles and the sides look puffed. Some slight browning around the edge is ok, but the top of the bars should be very light in color.

Remove the bars from the oven and allow them to cool to room temperature, for about 4 hours.

Once cooled, cut into 24 squares and dust with powdered sugar before serving.