Quiche

The Crust

1. Combine two thirds of flour with sugar and salt in the bowl of a food processor. Pulse twice to incorporate. Spread butter slices evenly over surface. Pulse until no dry flour remains and dough just begins to collect in clumps, about 25 short pulses. Use a rubber spatula to spread the dough evenly around the bowl of the food processor. Sprinkle with remaining flour and pulse until dough is just barely broken up, about 5 short pulses. Transfer dough to a large bowl.
2. Sprinkle with water. Then, using a rubber spatula, fold and press dough until it comes together into a ball. Divide ball in half. Form each half into a 4-inch disk. Wrap tightly in plastic and refrigerate for at least 2 hours before rolling and baking.
3. When ready to shape the dough, pull out one ball, set it on a well-floured work surface, and sprinkle with more flour. Use a tapered rolling pin to start rolling the dough out into a circle, lifting the dough and rotating it while rolling to achieve an even shape. Continue rolling, changing the angle of your rolling pin as you go to get an even shape and thickness. The finished dough should overhang your pie plate by an inch or two.
4. Pick up the dough by carefully rolling it around your rolling pin, using your bench scraper to help lift it off the work surface. Unroll it over a pie plate. Gently lift and fit the dough into the pie plate, getting down into the corners.
5. Use a pair of scissors to trim the dough so that it overhangs the edge by 1/2 inch all around. Tuck the overhanging edge(s) under itself all the way around the pie.
6. Flute the edges of the pie crust using the forefinger of one hand and the thumb and forefinger of the other. The pie shell is ready to be filled.

The Filling

1. Cut away the root and dark green leaves from the leeks and cut in half lengthwise. Run under cold water to remove sand. If the leeks are very sandy soak them for 15 minutes or so, then run under cold water again. Drain on paper towels. Cut into thin slices.
2. Preheat the oven to 350ºF. Heat the oil and butter over medium heat in a lidded skillet or saucepan and add the leeks and a pinch of salt. Cook gently, stirring, until they begin to soften. Turn the heat to medium-low, cover and cook gently until the leeks are very soft but not browned, stirring often, 10 to 15 minutes. If they begin to stick or brown, add a little more salt and/or a spoonful of water or wine. Stir in the garlic if using and cook for another 30 seconds to a minute, until fragrant.
3. Beat together the eggs in a medium bowl. Set the pie shell on a baking sheet to allow for easy handling. Using a pastry brush lightly brush the bottom of the crust and place in the oven for 10 minutes. Remove from the oven and set aside.
4. Add salt, pepper and the milk to the eggs and whisk together. Spread the leeks in an even layer in the crust. Sprinkle the cheese in an even layer on top. Pour in the custard filling. Place in the oven and bake for 30 minutes, or until set and just beginning to color on the top.
5. Remove from the oven and allow to sit for at least 15 minutes before serving.