In a large non stick pan melt butter and fry bacon, chillies, garlic and onion together until onion becomes soft. Add a little water to prevent burning or sticking if needed.
Add everything else and simmer covered for about half an hour (or until sweet potato is cooked through). Season to taste.
Tip
Add 1 to 2 teaspoons of cornflour (optional) to chicken stock if you prefer it a little thicker.