Add the chopped onions and sauté in 2 tablespoon of water for 3-4 minutes, then add the garlic and cook for another minute.

Add the sweet potatoes, vegetable broth, red pepper and brown rice.

Increase the heat and bring to a boil. Reduce heat and simmer, uncovered, until the sweet potatoes can be easily pierced with a fork and the brown rice is cooked, about 40 minutes. 

Use an immersion blender, puree the soup. 

Add soy milk to the soup, mix well Add salt and pepper to taste. 

Serve