Preheatthe oven to 325°F. Roast the beet and carrot chunks with some oil on a bakingsheet until soft (about 15 minutes).
Meanwhile,fry the mushrooms till golden in a splash of olive oil. Add the onion and garlic and sauté for about 5-7minutes.
Placethe beet, carrot, black beans, sautéed onion, and mushrooms into a foodprocessor or blender and pulse the mixture a bit. Add the flour, spices, andsalt, and pulse again, leaving some small chunks.
Formthe mixture into patties and place them on a preheated skillet with a fewspoonfuls of olive oil. Fry them on each side for about 2-3 minutes.
Toast the buns. Spread a sauce of your choice on thetop bun. Add a patty to the bottom bun. Top with your choice of burger fillingsand add more sauce if desired.