1. Preheat oven to 375 degrees Fahrenheit.
2. In very dry food processor or vita-mix, pulse the cashews into a sandy meal. Add the nutritional yeast and pulse until combined; pour into a large mixing bowl. Crumble drained tofu into the cashew mixture and mash with a fork until well blended; mixture will be somewhat dry and almost pasty at this point but don't dismay, it'll end up creamy and decadent. Set aside tofu mixture.
3. In large saute pan, heat olive oil over medium heat. Add onion and red pepper flakes; saute until onions are soft and golden, about 2 minutes. Add garlic and thyme, saute for 30 seconds more. Add mushrooms and saute until browned and tender, about 3 minutes. Add drained spinach and nutmeg, continue to cook until mixture is heated through and everything is combined. Stir in salt and pepper, mindful that the vegan cheese will add saltiness as well.
4. Mix spinach mixture with tofu in bowl, slowly add the 1/4 cup of water or broth as needed until a smooth creamy consistency is reached. Add vegan cheese and stir to combine. Pour mixture into the pie shell, pressing into the sides and mounding as needed to make it fit.
I like to give the top some texture by swirling lightly with the back of my spoon, you could also reserve some slices of sauteed mushroom or slivers of red bell pepper to decorate the top.
5. Place quiche on cookie sheet and put into middle of the oven. Bake for 35 to 45 minutes, or until quiche mixture is heated through and crust is browned. Remove from oven and let cool 15 minutes before serving. Cut into slices and enjoy!
Depending on the time of the year I serve this with a tomato salad or braised chard.
Source of recipe: I modified my mother's quiche recipe to make it vegan