Make pie dough the night before because it needs to chill in the refrigerator for at least 2 hours before rolling out and blind baking.

On a floured work surface, roll out one of the disks of chilled dough until you have a circle 12 inches in diameter. Carefully place the dough into a 9-inch pie dish. Tuck it in with your fingers, making sure it is completely smooth. Chill the pie crust in the refrigerator for at least 30 minutes.

Preheat oven to 400°F (204°C).

Line the chilled pie crust with parchment paper or aluminum foil. Fill with pie weights or dried beans. Bake until the edges of the crust are starting to brown, about 15-16 minutes. Remove pie from the oven and carefully lift the parchment paper/aluminum foil (with the weights) out of the pie. Prick holes all around the bottom crust with a fork. Return the pie crust to the oven and bake until the bottom crust is just beginning to brown, about 7-8 minutes.

Remove crust from the oven. Reduce oven temperature to 350°F (177°C).

Heat olive oil and garlic in a skillet over medium heat. Add the spinach. Cook and stir until wilted. Set aside.

Whisk the eggs and milk together until combined. Stir in the sun-dried tomatoes, goat cheese, spinach, salt, and pepper. Pour into warm pre-baked crust.

Bake the quiche until the center is just about set, about 45-60 minutes. Allow to cool for 15 minutes before slicing and serving.