Heat oven to 350°F (175°C).

Press a large piece of parchment paper (meant to cover a half-sheet pan) across the bottom and up the sides of a 9×13-inch baking pan. Don’t worry if it’s wrinkly.

In the work bowl of a food processor or the bowl of a stand mixer, combine the flour, sugar, and salt on low speed. Add the diced butter. In a food processor, pulse the machine until the butter is fully incorporated, then run it until the dough begins to ball together. This can take 1 to 2 minutes, but it will come together. In a stand mixer, lock the top in place and mix on low speed until the butter is in smaller pieces, then raise the speed slightly and mix until the butter and flour are evenly combined, scraping down the bowl as needed.

Tip the crust dough into the prepared pan and press it evenly across and then 1/2-inch up the sides of the bottom. Bake the crust for 15 to 20 minutes, until very lightly browned.

Place the sugar in a large bowl and finely grate the zest of your lemons into it. Use your fingertips to rub the zest into the sugar and salt, releasing as much flavor as you can and breaking up the zest strips a little. Juice your lemons until you have 1 cup of juice. Whisk eggs, flour, and juice into sugar-zest mixture until evenly combined.

Pour the lemon filling over the parbaked crust (still warm is fine).

Bake for 25 to 30 minutes or until the center barely jiggles when you shimmy the pan.

Let cool to room temperature before serving, or pop them in the fridge if you prefer them cold.

Use the parchment paper to help slide the bars out of the baking pan and onto a cutting board. Cut into 24 generous squares, or smaller ones if you prefer. Dust with powdered sugar.

Leftover lemon bars will keep in the fridge for one week. They will also freeze well between sheets of parchment paper.