Preheat oven to 220 degrees C and cut the sweet potatoes and shallots in half.
Bake the sweet potatoes, garlic and shallots for about 30 minutes. Skin the potatoes and garlic and puree with an immersion blender. Add the shallots and mix.Peel and grate ginger.Add the ginger, thyme, cayenne pepper, chilli, salt and pepper to the pot and cook for a minute.Stir in the coconut milk and bring to a boil. Reduce heat and let it simmer for about 15 minutes.