Preheat the oven to 400ºF or 200ºC.

Heat the oil in a large skillet, then add the garlic and onion, and cook over medium-high heat until they start to golden brown.

Add the mushrooms and the cherry tomatoes and cook until golden brown.

Then add the spinach and cook until just wilted. 

Remove the skillet from the stove and set aside.

Add all the remaining ingredients to a food processor (tofu, nutritional yeast, plant milk, cornstarch, pepper, salt, black salt, and turmeric) and blend until smooth. Set aside.

Pour the filling into the pie crust-lined pan. I use a 9-inch or 23 cm round pie pan.

Spread half of the sautéed veggies evenly over the bottom of the crust. Pour the tofu mixture over the veggies and add the remaining veggies on top.

Bake for 35 to 45 minutes or until firm and golden on top. Remove from the oven and let it rest for 15 minutes to cool slightly before slicing.

Serve your vegan quiche warm or cold as part of a vegan brunch along with some toasted gluten-free bread and a vegan sausage.

Keep the leftovers in an airtight container in the fridge for 5 to 7 days or in the freezer for up to 3 months.