°4 Tbsp (½ stick) unsalted butter, melted and cooled, plus pan
°1½ c graham cracker crumbs
°¼ c sugar
°2 large egg yolks
°1 can (14 oz) sweetened condensed milk
°½ cup fresh lemon juice (about 3 lemons)
Preheat the oven to 350°F. Brushing an 8-inch square baking dish with butter. Line the bottom with parchment paper, leaving a 2-inch overhang on both sides.
In food processor, finely grind graham crackers. Add the sugar and butter and stir. Press the mixture into the bottom of the prepared baking dish and 1 inch on the sides. Cook until lightly browned, 8 to 12 minutes. Let cool for 30 minutes.
Meanwhile, make the filling. In a large bowl, whisk together the egg yolks and condensed milk. Add lemon juice; whisk until mixture is smooth. Pour filling into cooled crust; carefully spread on edges.
Bake for about 15 minutes. Cool in the pan on a wire rack and refrigerate for at least 1 hour before serving. Using the overhanging parchment paper, gently lift the lemon square out of the pan and transfer to a cutting board. Using a serrated knife, cut into 16 squares, wipe the knife with a damp kitchen cloth between each cut.