1-First Step: Preheat and Prepare Pan
Heat your oven to 350°F (175°C). Line a 9×13 inch baking dish with parchment paper, leaving an overhang for easy removal of the bars.

2-Second Step: Make the Crust
In a medium bowl, whisk together 2 1/2 cups flour, powdered sugar, salt, and lemon zest. Pour in the melted butter (and vanilla extract if using) and mix until a dough forms. Press evenly into the prepared baking pan and bake for about 20 minutes or until lightly golden.

3-Third Step: Prepare the Filling
While the crust bakes, pulse the granulated sugar with lemon zest in a food processor until fragrant and light yellow. If you don’t have a processor, finely mince the zest and mix with sugar by hand. In a large bowl, whisk the eggs thoroughly, then stir in the lemon-zested sugar, remaining 1/2 cup flour, fresh lemon juice, and salt until smooth and fully incorporated.

4-Fourth Step: Bake the Filling
Pour the lemon filling over the warm crust. Bake for 25 minutes, rotating the pan halfway through, until the center is just set with a slight jiggle. Avoid overbaking to prevent cracking.

5-Final Step: Cool, Dust, and Serve
Let the lemon bars cool at room temperature for about an hour, then refrigerate for at least 2 hours to fully set. Dust with powdered sugar before slicing. For cleaner cuts, use a sharp knife dipped in hot water and dried between each slice.