Slice (I peel everything, but that's your preference) the sweet potato, cover generously with molasses, and cook in the oven on a low heat, 300F or so, until soft.
While the s potato is cooking get the rest of the soup going. Slice the plums and the apple, and peel the orange. I put each slice in whole because it looks prettier. Add them to a pot and cover with water. How much water depends on how soupy you want your soup. Reserve the coconut milk and the banana until closer to the end.
Bring to a boil then turn down the heat to a low-med simmer. When the potato is done, add that, and the seasonings. Let it cook for a little while longer, until its close to the taste you want it. The spices will get a little stronger, but not much. Blend or mash the banana into the coconut milk, and add that too.
Serve either hot or cold in a big mug. Complete comfort food!