Preheat the oven to 375 degrees F. Roll out the pie dough into a circle on a floured surface. Fold the dough into quarters and unfold over a 9-inch pie pan, leaving a 1 inch overhang. Trim and crimp the edges. Put the pie plate in the fridge or freezer for a few minute to firm the dough back up.
I personally like to parbake the crust a little at this point, but this step is not absolutely necessary. If parbaking, put parchment paper in the bottom and fill with pie weights or dried beans. Bake for about 10 minutes.
Cut the bacon into 1/2 inch pieces and sautée over medium heat until browned, stirring frequently. Remove the bacon with a slotted spoon, leaving a tablespoon of grease in the pan.
Add the sliced leeks and sautée until tender and browned. Add to bacon.
In the meantime, whisk together the eggs, milk, herbs, salt and pepper.
To fill the quiche, put half the cheese in the bottom, then add the leeks and bacon. Sprinkle the rest of the cheese evenly over the top, and pour in the egg mixture.
Bake for 45 minutes, or until the center has set and the top has golden brown spots.