Preheat the oven to 350 degrees. Grease an 8-inch square baking dish with melted butter. Line bottom with parchment paper, leaving a 2-inch overhang on the sides.
In a food processor, grind the Graham-cracker squares. Then add sugar and butter and mix. Press mixture into bottom of pan with 1 inch up. Bake until slightly browned, 8 to 12 minutes. Cold crust, 30 minutes.
To prepare the filling: In a large bowl, whisking egg yolks with condensed milk. Adding lemon juice also whisking To smooth. Pour filling To cooled crust. Carefully spreading to edges.
Bake To fully cooked, about 15 minutes. cool in the pan on the rack; And refrigerate at least an 1 h before serve . Using a load of parchment paper, lift it from the pan, and transfer it to a cutting board. With a serrated knife, cut into 16 squares, wipe knife with a damp kitchen towel between each cut.
Enjoy !