1. Preheat oven to 375°. Bake pastry shell for 10–12 minutes or until browned. Remove shell from oven, and set aside. Leave oven on.
2. Heat 1 1/4 teaspoons oil over medium heat in a large nonstick skillet; add shallots. Add spinach, and cook 2–3 minutes or until wilted. Add 1/4 teaspoon salt and a dash of pepper. Transfer to a plate; set aside
3. Using the same pan, heat remaining oil, and cook mushrooms about 6 minutes or until browned on both sides. Remove from heat. Season with remaining 1/4 teaspoon salt and 1/4 teaspoon pepper.
4. Sprinkle 1/3 cup Parmesan cheese over bottom of pastry crust. Top with spinach and mushrooms.
5. In a separate bowl, whisk together soy milk with egg and egg whites. Pour into shell. Top with remaining 1/3 cup Parmesan, and bake for 45–50 minutes or until top is firm and golden brown. Cut into wedges and serve.