Add 1 tablespoon of oil to a large skillet and heat over medium heat. Add the diced onion and ½ teaspoon of salt. Sauté until translucent, 3-5 minutes.
Add the mushrooms and sausage. Sauté for another 4-5 minutes.
Lastly, add in the chopped spinach and sauté until wilted. Remove from heat. Add salt and black pepper to taste and set aside.
In a high-speed blender, add the tofu, vegan cheese, non-dairy milk, chickpea flour, nutritional yeast, remaining ½ teaspoon of salt, and turmeric. Blend until completely smooth.
Combine the ingredients in a quiche dish. Smooth the top with the back of a spatula.
Bake for 45 minutes to 1 hour, depending on how custard-like you want it.
Slice and serve!