Preheat the oven to 375°F.
To make the dough in a food processor, combine the flour, salt and butter in the processor and process until the mixture resembles coarse crumbs, about 10 seconds. With the machine running, add the ice water through the feed tube and pulse quickly 5 or 6 times, or until the dough comes together and starts to pull away from the sides of the container. Gather the dough into a ball, flatten it into a disk, and wrap in plastic wrap. Refrigerate for at least 1 hour.
To make the dough by hand, combine the flour, salt and butter in a medium bowl and mix with a pastry blender or your fingertips until the mixture resembles coarse crumbs. Add the water 1 tablespoon at a time and mix until the dough comes together and is no longer dry, being careful not to overmix. Form into a disk, wrap in plastic wrap and refrigerate for at least 1 hour.
On a lightly floured surface, roll out the dough to an 11-inch circle. Fit into a 9-inch fluted tart pan with a removable bottom and trim the edges. (Alternatively, a 9-inch pie pan can be used.) Refrigerate for at least 30 minutes.
Line the pastry with parchment paper and fill with pie weights or dried beans. Bake until the crust is set, 12 to 14 minutes. Remove the paper and weights and bake until golden brown, 8 to 10 minutes. Remove from the oven and cool on a wire rack. Leave the oven on.
In a medium skillet, cook the bacon until crisp and the fat is rendered, about 5 minutes. Remove with a slotted spoon and drain on paper towels. Using the bacon fat, sauté the leeks until very soft and caramelized, about 15-20 minutes.
Arrange the bacon, cheese and leeks evenly over the bottom of the baked crust.
In a large bowl, beat the eggs, yolks and half and half. Add the remaining ingredients and whisk to combine. Pour into the prepared crust and bake until the custard is golden, puffed and set yet, still slightly wiggly in the center, 30 to 35 minutes.
Remove from the oven and let cool on a wire rack for 15 minutes before serving.