Preheat your oven to 200°C (390°F) and lightly coat a 10-inch tart dish with olive oil.
Use an oil brush to gently brush olive oil in-between each layer of the filo pastry, gently lay it over the tart dish, press it into the edges and cut away any part that is hanging over the edge.
Fry the onion and garlic in a small splash of olive oil in a frying pan until golden and caramelised.
Mix the chickpea flour, nutritional yeast, baking powder, salt, ginger and turmeric in a medium bowl, whisk in the plant-based milk and then the chopped spinach and fried onions and garlic. Pour this mixture into the tart dish.
Lay the sundried tomatoes (and any other topping on top and bake in the oven for 25 minutes or until the pastry has browned slightly and the top of the quiche has started to crack. Let cool before serving.
* I used almond milk but any plant-based milk will work.