Rinse quinoa in a sieve under cold water. Dice sweet potato, bell pepper, and onion. Chop garlic. Drain and wash beans and corn, and chop walnuts.
Heat oil in a pot over medium-high heat and fry vegetables for approx. 3 min. Add chili powder, paprika powder, cayenne pepper, cumin, and oregano to the pot and mix well. Sauté for approx. 4 – 5 min.
Add crushed tomatoes, vegetable stock, and quinoa to the pot. Season with soy sauce, cane sugar, salt and pepper. Bring to a boil and let cook, covered, for approx. 15 – 20 min. During the last 5 min., add black beans, kidney beans, corn, and walnuts to the pot.
Chop cilantro. Halve, pit and dice avocado. Season with salt, pepper, and lime juice to taste. Serve with chopped cilantro, avocado and soy yogurt. Enjoy!