CRUST: Preheat oven to 375 degrees F (190 C), and set out a standard-size (9-inch) pie pan. If making homemade pie crust, prepare it at this time. Note: With both homemade and store-bought crust, the crust needs to par-bake for 20 minutes before adding the vegetables and egg mixture.
Once the crust has par-baked, lower your oven temperature to 350 degrees F (176 C) and place the crust on a baking sheet to catch any spillage that might happen when baking the quiche.
To a large skillet, add vegan butter and heat on medium until it's completely melted. Next add the sliced leeks, sliced mushrooms, thyme, and 1/2 teaspoon each of salt and pepper (adjust if altering batch size). Cook on medium-low until the leeks are soft, the mushrooms are tender, and all of their liquid has evaporated from the pan, about 8-10 minutes. Once the leeks and mushrooms are cooked, add the spinach to the pan and wilt. Remove from the heat and set aside.
To a medium mixing bowl, add eggs, dairy free milk, and the remaining 1/2 teaspoon each of salt and pepper (adjust if altering batch size). Whisk very well until fully incorporated.
To your par-baked pie crust, add the cooked vegetables and spread evenly to fully cover the bottom of the crust. Next pour the egg mixture over the vegetables. If using the optional dairy-free cheese, top the quiche with an even layer of the shreds.
Bake in the preheated oven for 45-50 minutes or until the center barely jiggles. When fully cooked, it will be well set.
Let cool for 20 minutes before serving. Serve warm or cold from the refrigerator. Store leftovers in the refrigerator for up to 3 days.
Video
Notes
*Nutrition information is a rough estimate calculated without optional ingredients.