Preheat oven to 375 degrees. Spray a glass pie pan with cooking spray and set aside. Saute the spinach and salt in a very small amount of water until the spinach is limp. Revove from heat. Add flour, bread crumbs, and a few dashes of nutmeg; mix well. I used an immersion blender to mix it more uniformly. Pat into prepared pan using a fork, then used moistened hands to mold the crust. Bake for 15 minutes. Fill immediately OR let cool, wrap tightly, and refrigerate.
Saute onion and salt in a little water in a nonstick skillet until onion is soft. Add mushrooms and lemon juice. Cook, stirring often, about 5 to 8 minutes. Sprinkle in the flour, dry mustard, basil, and thyme; stir in. Cook and stir 5 minutes, then remove from heat. In a bowl, combine the canellini beans, pimentos, and tahini. Blend with immersion blender (or in regular blender) until smooth. Stir in the nutritional yeast, ground flaxseed, soy yogurt, and pepper until well blended. Stir in the mushroom mixture. Pour into prebaked pie crust, and lightly dust the top with paprika. Bake 30 minutes or until set. Let cool at least 10 minutes before serving. Can be served hot, warm, or at room temperature.
The crust can be made a couple of days in advance, tightly wrapped in plastic wrap, and stored in the refrigerator. The entire pie can be made up to two days ahead and stored in the same way. To reheat, let pie come to room temperature, then cover lightly with foil. Reheat in a 300 degree oven about 20 to 30 minutes.