In a nonstick pan over medium heat, sauté onions in a bit of olive oil until caramelized, about 20 minutes. Set aside.
Sauté mushrooms for 5-7 minutes, until they've shrunk and shed their excess liquid. Set aside. In the meantime, preheat oven to 350°F.
In the bowl of a food processor, combine tofu, chickpea flour, water and spices and process until smooth. Stir in caramelized onions, mushrooms and asparagus.
Spread batter evenly in a greased quiche or pie pan and bake for 1 hour. Remove from oven and allow to cool slightly before slicing and serving.