Press some of the water out of the tofu by wrapping it in towels and placing it under something heavy (like a few plates) while you prepare the spinach and mushrooms
Preheat the oil in a large frying pan over medium heat. Cook the mushrooms for about two minutes, then add the spinach and cook until just wilted. Set aside.
In a food processor, combine the tofu, the seasonings, and the nutritional yeast. Process until creamy. You will want it to be somewhat thick, because it won't thicken as it cooks, but you can add a little water if you need to.
Spoon the tofu mixture into a large bowl. Fold in the cheese, then add the spinach and mushrooms. Stir gently to combine.
Spoon into the pie crust. Bake at 425 for about 30 minutes, until the quiche is heated through and the pie crust is golden brown. If you'd like you can sprinkle a little cheese for the last 10 minutes of baking.
Recipe by at https://coachdebbieruns.com/another-take-on-quiche/