Step 1: Make the Crust

• Combine flour and butter: In a food processor, pulse the flour, salt, and cold diced butter until the mixture resembles coarse crumbs.
• Add ice water: Gradually add the ice water, one tablespoon at a time, and pulse until the dough begins to come together.
• Chill the dough: Form the dough into a disk, wrap it in plastic wrap, and refrigerate for at least 30 minutes.

Step 2: Prepare the Filling

• Cook the ham: If using uncooked ham, cook it in a skillet over medium heat until browned. Otherwise, use pre-cooked ham and dice it into small cubes.
• Grate the cheese: Grate the Gruyère cheese and set aside.
• Whisk the eggs and cream: In a medium bowl, whisk together the eggs, heavy cream, Dijon mustard, nutmeg, salt, and pepper until smooth and well combined.

Step 3: Assemble the Quiche

• Roll out the dough: Preheat your oven to 375°F (190°C). Roll out the chilled dough on a lightly floured surface to fit a 9-inch pie dish. Press the dough into the dish, trimming any excess.
• Blind bake the crust: Line the crust with parchment paper and fill it with pie weights or dried beans. Bake the crust for 15 minutes, then remove the weights and bake for another 5 minutes until lightly golden.

Step 4: Fill the Quiche

• Add the ham and cheese: Spread the diced ham and grated cheese evenly over the bottom of the pre-baked crust.
• Pour the egg mixture: Pour the egg and cream mixture over the ham and cheese, making sure it fills the crust evenly.

Step 5: Bake the Quiche

• Bake the quiche: Place the quiche in the preheated oven and bake for 35-40 minutes, or until the filling is set and the top is golden brown.
• Let it cool: Remove the quiche from the oven and let it cool for about 10 minutes before slicing and serving.