Method:
Preheat oven to 350°F. Lightly grease an 8-inch loaf pan with oil; set aside. Heat oil in a large skillet over medium-high heat. Add mushrooms, salt and pepper and cook, stirring occasionally, until mushrooms are golden brown, 6 to 8 minutes.
Meanwhile, put beans, oats and 1/2 cup water into a food processor and pulse until almost smooth. In a large bowl, combine mushrooms, bean mixture, quinoa, peas, parsley, tomatoes, onion, salt and pepper. Transfer mixture to prepared loaf pan, gently pressing down and mounding it in the middle. Bake until firm and golden brown, 1 to 1 1/4 hours. Set aside to let rest for 10 minutes before slicing and serving.