Adzuki beans and milk go well together and warm you right up. Instead of sweet red bean soup, you could use the broth from black soy beans or boiled adzuki beans.
Apparently there's something like this sold (I heard from a friend). I've never had it before so I just used my imagination to create my own version.
The ingredient amounts are just approximations. Adjust the sweetness of the red bean soup to taste.
Enjoy Japanese food around the world.