Preheat oven to 350 degrees. Unwrap and lay room temperture pie crust into a deep 9-inch pie dish. I do not arrange the edges because I like the rustic look, but you can totally pinch and fold to make it look pretty. Pierce the bottom and sides several times with a fork. Bake for 8-10 minutes or until it is just barely starting to cook and brown. Remove and set aside.
Prepare sweet potatoes and onion by placing them in a large bowl and tossing with extra virgin olive oil and freshly cracked pepper. Spread in a single layer on a rimmed baking sheet and bake at 350 degrees for 20-25 minutes, or until potatoes are fork tender.
Combine crumbled bacon, chopped parsley, beaten eggs, half & half, chopped rosemary, fine sea salt and 1 1/2 cups finely shredded Gruyere cheese in a large mixing bowl, stirring well to combine.
Transfer sweet potato and red onion mixture to prepared pie crust. Arrange ingredients as easily as possible so you get a taste of everything in each in bite.
Pour egg mixture over sweet potatoes and red onion until just reaching the top of the pie crust.
Place into the oven and bake for 25-35 minutes, or until center is set. Top with remaining 1/2 cup Gruyere cheese while still warm. Serve immediately or refrigerate and re-warm at 350 degrees for 10 minutes.
If you've tried this recipe, please come back and let us know how it was!
Bacon is optional.A deep dish pie plate is necessary.If the edges of the pie crust are starting to brown, loosely place a sheet of aluminum foil over the top.