Start with a thawed but cold 9” gluten-free deep dish pie crust. Leave the pie crust in the fridge until you’re ready to fill it. See our recipe for a homemade gluten-free pie crust.
Preheat the oven to 350 ℉.
In a small frying pan, sauté the butter with the onion (over low heat) until the onions have softened and look clear.
Add the garlic to the frying pan (still over low heat) and sauté for an additional minute or two. Be careful not to burn the garlic.
Remove the frying pan from the heat and set it aside for now.
In a medium bowl, whisk together the half and half, sour cream, eggs, salt and black pepper until well combined. Set aside for now.
Sprinkle the onion and garlic evenly over the base of the unbaked crust.
Be sure to squeeze all the extra liquid out of the thawed spinach. Use paper towels to squeeze out as much water as possible. Extra water in the spinach will water down this recipe and the quiche won’t set properly.
Start to sprinkle the spinach, shredded cheddar and shredded Parmesan into the pie shell. Alternate layers of spinach and cheese while sprinkling into the pie shell.
Set the pie plate on a baking sheet to catch any spills that may happen during baking. This also makes it easier to place the quiche into the oven and remove it from the oven.
Pour the egg mixture evenly over the other filling ingredients in the pie crust.
Bake for 50 to 55 minutes. The sides of the quiche will look set and the middle will be slightly wobbly. Remove from oven and let sit on top of the stove for 25 minutes before slicing and serving. This allows the quiche time to set properly after removing from the oven.
Serve warm.
Notes
Allow the leftovers to cool to room temperature, then store leftovers in an air-tight container in the refrigerator for up to 3 days.
Be sure to squeeze all the excess water out of the thawed spinach. If there is excess water in the spinach, it will prevent the quiche from setting properly. Keep in mind that the 10 ounces of spinach called for in this recipe is the weight of the spinach when it is frozen. The weight is reduced by more than half after you’ve squeezed the excess water out and that is exactly what we’re looking for here. After squeezing all the excess water out, you’ll end up with about 4 ounces of chopped spinach and that’s okay.
To freeze: After the quiche has fully cooled, wrap individual pieces of quiche well in plastic wrap and place them in a plastic freezer bag or a freezer-safe container in the freezer for up to 2 months. Thaw the quiche in the refrigerator overnight.
To reheat: in the oven at 350°F or in the microwave before serving.
Prebaking the crust is not necessary for this recipe but if you want your crust to be crispier you can par-bake (partially bake) the pie crust before adding fillings. See our gluten-free pie crust recipe for instructions on prebaking and par-baking the pie crust.