If you do not already have cooked quinoa, prepare it at this time. 1/4 cup uncooked quinoa will yield ~3/4 cup cooked.
Heat a large skillet over medium-low heat and add some nonstick spray or a bit of olive oil. Once hot add the onion and sauté, seasoning with a pinch each salt and pepper.
When the onions are soft – about 5 minutes – turn up the heat to medium and add the mushrooms. Season with another pinch of salt and pepper and cook until the mushrooms and onions are slightly browned and fragrant – about 3 minutes.
Remove from heat and add black beans and mash. You’re looking for a rough mash, so you can leave a bit of texture if you want.
Transfer the mixture to a mixing bowl and add the quinoa, beets, spices and stir. For even more flavor, add a shake of vegan worcestershire or A-1 sauce (optional). Taste and adjust, adding more salt for overall flavor (we added another 1/4 tsp).
Lastly, add the walnut meal a little at a time until the mixture is able enough to form into patties. Set in the fridge to chill while your oven preheats to 375 degrees F (190 C) (skip this step if cooking on the stovetop - see notes).
Coat a baking sheet with nonstick spray or olive oil. Form mixture into roughly 1/3-cup sized patties (8-9 patties // adjust if altering batch size). I use a peanut butter jar lid lined with plastic wrap to get the perfect shape (a tip I learned from Iowa Girl Eats). You can also just take handfuls and mash them into loose patties.
Arrange burgers on a baking sheet and brush or spray the tops with olive oil. Bake at 375 F (190 C) for a total of 30-45 minutes, gently flipping after 25-30 minutes. Cook longer to dry them out even more and achieve more crisp, but it’s not necessary.
Serve on small buns or atop mixed greens with desired toppings. See notes for freezing instructions.
*For a quicker prep time, you can use a food processor to chop the walnuts, mushrooms, and beets. Use the "s blade" for the walnuts and mushrooms and the grater attachment for the beets. *Prep time does not include cooking quinoa. You can use leftover quinoa. *For a quicker cook time, form into slightly thinner patties and brown in a skillet over medium heat lightly coated with olive, avocado or coconut oil. Cook until brown on both sides – 3-4 minutes each. NOTE: This method doesn’t get them as well done in the middle, but the crust is more pronounced. * FREEZING: If you don’t want to cook the whole batch at once, form into 10 patties, par-bake them at 375 degrees F (190 C) for 15-20 minutes. Then cool and stack between layers of parchment paper and cover. Freeze for up to a few weeks. To cook, place on baking sheet still frozen and bake at 375 degrees F (190 C) until desired texture/color is reached - roughly 25-35 minutes. *If they are falling apart when flipping, that likely means they were formed too large or flipped too early. If that happens with one burger, cook longer before flipping the rest. *Nutrition information is a rough estimate.