In a saucepan, bring the chicken stock to a low boil. Slice the celery ribs down the center, then chop into thin pieces and add to the stock. Allow the celery to cook 5-10 minutes, or until it becomes tender. Turn off the heat and set aside.
Place a large stockpot over medium heat and add the olive oil. When warm add the cubed chicken and cook through, allowing the bits to become slightly golden. Use a slotted spoon to remove the chicken (reserve aside in a bowl).
After removing the chicken, add the chopped onion to stockpot. Cook until the onion is beginning to turn golden, then add the garlic and cook for another minute. You're ready to add the bananas! Just slice the bananas into manageable chunks then plop them into the onion/garlic goodness. Use a fork or a potato masher to break down the bananas. There will probably be some lumps--that's perfectly fine.
Once mashed, add the spices and seasonings (ginger, thyme, rosemary, cayenne, salt and pepper). Make sure to start small and add more to taste. Remember that while you can always *add* more cayenne its near-impossible to remove!
Let the newly-spiced banana mixture warm for a minute then add the milk, garbanzo beans, and reserved cooked chicken. Once this is thoroughly mixed, also add the reserved celery and chicken stock and the butter. All the kiddies should now be in the pool. Bring this up to a very low boil, and if necessary allow it to reduce until the liquid has a texture that is slightly creamy.
Serve warm over rice.