In a large pot over medium heat, saute diced onion in 2 teaspoons water. Add diced sweet potato and spices. Cover and cook for 5 minutes.
Add 3 cups vegetable broth and bring mixture to a low boil on high heat. Lower heat to medium and add quinoa, beans, corn and cinnamon stick.
Cover and cook for 30 minutes or until sweet potatoes are fork tender. Stir in additional cup of vegetable broth. Taste and add more seasonings as needed. Remove from heat.
Remove cinnamon stick and top with fresh cilantro, lime juice, and avocado.