Preheat the oven to 425 degrees F.

Prepare the potato crust by combining sliced red-skinned potatoes, melted butter, Parmesan cheese, salt, and pepper in a medium bowl.

Coat a 9-inch pie plate with cooking spray.

Arrange the potato slices in concentric circles on the bottom and sides of the pie plate, ensuring no gaps.

Bake the potato crust for 25 to 30 minutes, or until light golden brown.

Remove the crust from the oven and cool on a rack.

Reduce the oven temperature to 375 degrees F.

Prepare the filling by cooking pancetta in a medium saucepan over medium heat until browned and crispy.

Remove the pancetta and set aside on a paper towel, reserving 1 teaspoon of the drippings in the pan.

Add spinach to the pan and cook until barely wilted, about 30 seconds.

In a large bowl, whisk together eggs, milk, Parmesan cheese, and black pepper.

Stir in the cooked spinach.

Pour the egg mixture into the potato crust.

Sprinkle the sun-dried tomatoes and cooked pancetta evenly over the egg mixture.

Bake the quiche for 30 to 40 minutes, or until the eggs are set and golden brown.

Check for doneness by inserting a small sharp knife into the center of the eggs.

If the knife comes out clean, the eggs are set.

Let the quiche cool for 10 minutes before cutting into wedges and serving.