To a large skillet over medium-high heat, add the oil and leeks. Sauté for 5-7 minutes until leeks become soft. Add spinach to the pan and cook an additional 1-2 minutes until spinach is wilted.
In a large bowl, whisk together eggs, heavy cream, salt, and pepper. Stir in the cooked leeks and spinach, sun-dried tomatoes, and half of the goat cheese.
Preheat oven to 400° F.
Roll out pie dough on a well-floured surface to about a 13-14 inch circle. Transfer to a 9 or 10 inch deep dish tart pan, deep dish pie pan or springform pan, and press dough into bottom and up the sides of the pan. Pour in the egg mixture and sprinkle with remaining crumbled goat cheese.
Place the quiche onto a parchment lined baking sheet (do not skip this step; the oil from the sun-dried tomatoes will bubble over). Bake for 40 minutes until the edges are lightly golden brown, then loosely cover with tinfoil and continue baking for another 30-45 minutes until the quiche is set around the edges and slightly jiggly in the center. To check if the quiche is done, insert a knife halfway between the side and center of the filling - it will come out clean if it's done.
Remove from oven and let rest for at least 1 hour before serving. Slice and enjoy!