One of the easiest things I’ve ever made and I managed to overcook it a bit. It was still good.
1 1/2 cups flour
1/2 cup powdered sugar
1/4 teaspoon salt
9 tablespoons very cold, unsalted butter, cut into small pieces
1 large egg
1 lemon rinsed and dried
1 1/2 cups sugar
1 stick unsalted butter, cut into chunks
4 large eggs
2 tablespoons (14 grams) cornstarch
1/4 teaspoon table salt
Pulse the flour, sugar and salt together in the bowl of a food processor. Scatter the pieces of butter over the dry ingredients and pulse until the butter is coarsely cut in. Stir the yolk, just to break it up, and add it a little at a time, pulsing after each addition. When the egg is in, process in long pulses–about 10 seconds each–until the dough, which will look granular soon after the egg is added, forms clumps and curds. Turn the dough out onto a work surface and, very lightly and sparingly, knead the dough just to incorporate any dry ingredients that might have escaped mixing. Chill the dough, wrapped in plastic, for about 2 hours before rolling.
To roll the dough: Butter a 9-inch fluted tart pan with a removable bottom. Roll out chilled dough on floured sheet of parchment paper to 12-inch round, lifting and turning dough occasionally to free from paper. Using paper as aid, turn dough into 9-inch-diameter tart pan with removable bottom; peel off paper. Seal any cracks in dough. Trim overhang to 1/2 inch. Fold overhang in, making double-thick sides. Pierce crust all over with fork.
To fully or partially bake the crust: Center a rack in the oven and preheat the oven to 375 degrees F. Butter the shiny side of a piece of aluminum foil and fit the foil, buttered side down, tightly against the crust. Put the tart pan on a baking sheet and bake the crust for 20 to 25 minutes.
Carefully remove the foil. If the crust has puffed, press it down gently with the back of a spoon. Bake the crust about 10 minutes longer to fully bake it, or until it is firm and golden brown, brown being the important word: a pale crust doesn’t have a lot of flavor. (To partially bake it, only an additional 5 minutes is needed.) Transfer the pan to a rack and cool the crust to room temperature, and proceed with the rest of your recipe.
Cut the lemon in half then slice the lemon halves into thin wheels, remove any seeds, and toss the rounds — lemon flesh and peel — sugar and chunks of butter into the container of a food processor. Process, scraping down the sides of the container as needed, until the lemon is thoroughly pureed. Add the eggs, cornstarch and salt and pulse until the batter is smooth.
Pour into prepared tart shell. It will fill it completely but if due to slight variances in tart pans, egg sizes, lemon sizes or crust thickness, you have too much, do not pour it past the top of of your crust or it will become difficult to unmold later.
Bake for 35 to 40 minutes or until the filling is set. You can test this by bumping the pan a little; it should only jiggle slightly. In my oven, I find that the point at which the filling is set is also when it starts to get very light brown on top.
Let cool on rack, unmold tart pan and serve cold.