1. Preheat oven to 350° F.
2. Heat a skillet over medium heat. Once hot, add 2 tablespoons of olive oil, swirl to coat the pan, and add the onion. Sauté, stirring frequently, until onion is just starting to become translucent. Add the mushrooms and continue to sauté until onion is cooked through and mushrooms have released their juices, 8-10 minutes total. Add the garlic and seasonings and cook for 1-2 minutes, until fragrant.
3. While the vegetables cook, pulse the walnuts and oats in a food processor until they are a coarse meal consistency.
4. Once the vegetables are finished cooking add them to the food processor and process, scraping the sides as necessary, until the mixture comes together and looks a little sticky.
5. Pour the remaining 2 tablespoons of olive oil into a small bowl. Wet your hands lightly and roll the mixture, one tablespoon at a time, into a ball, then roll in the olive oil. Place on the baking sheet and continue until the mixture is all rolled, wetting your hands as necessary to prevent sticking.
6. Bake for 30-35 minutes, until browned and slightly firm to the touch. Serve immediately.
Note: Natural Grocers Brand Bulk ingredients are packaged in a plant that processes gluten.