Prepare the pie dough: Mix flour and salt in a large bowl. Cut the butter into small cubes and add to the flour. Using your fingers, rub the butter into the flour until the mixture resembles breadcrumbs.
In a small bowl, whisk half an egg yolk with 2 tbsp water. Gradually mix this mixture into the flour just until the dough comes together. You may not need all of the egg-water mix.
Form into a flattened ball, cover with plastic wrap, and refrigerate 30 minutes. The refrigerated dough will keep up to a week tightly wrapped. If the dough gets too hard in the fridge (butter solidifies), you’ll need to let it sit at room temperature until just workable before rolling out.
Blind bake the crust: Preheat the oven to 200 °C (392 °F) Roll out the chilled crust to fit your pie pan (I used a 25 cm/10 in ceramic pie pan). Lay the crust in the pie pan. Trim off any excess crust. Prick the bottom of the crust with a fork in several spots to avoid puffing in the oven. Place pie weights (such as dried beans) on top of parchment paper in the crust. Bake at 200 °C for 15 minutes. Remove the parchment paper and pie weights, then bake another 10 minutes.
Make the filling: Cook the lardons in a pan over medium heat until nicely browned but not crispy. Whisk together the eggs, crème fraîche, salt, and pepper.
Arrange the cooked lardons on the bottom of the pie crust, leaving the rendered fat in the pan. Pour the egg mixture over the lardons.
Bake in the oven at 200 °C (392 °F) for 25 minutes or until the top is golden brown and the center of the quiche is set.