Heat oil in a large saucepan or deep skillet over medium fire. Add in onion, and sauté until softened, about 2-3 minutes. Add in garlic and ginger, and cook for another minute, until everything is aromatic.
Add in chicken, and continue cooking for another 3-4 minutes, until the meat is just cooked and begins to brown. Add in Sweet & Spicy Curry Powder, and stir well to coat chicken evenly.
Add in sweet potatoes, chicken broth, and tomatoes. Bring soup to a boil. Turn fire down to simmer, cover pan, and cook for about 10 minutes – stirring occasionally.
Whisk in peanut butter and coconut milk. Then sprinkle in brown sugar & salt (I used Sweet Ginger Sea Salt), stirring well to combine. Taste, and if necessary, adjust the peanut butter, coconut milk, or seasonings. Bring stew to a simmer and cook for another 20-25 minutes, or until the sweet potatoes are softened.
Finally, add freshly ground black pepper, and garnish with cilantro & crushed peanuts.