In a large pot, heat the vegetable oil over medium heat.
Add the meat pieces and brown them on all sides. Remove the meat from the pot and set aside.
In the same pot, add the finely chopped onion and sauté until translucent, about 5 minutes.
Stir in the minced garlic and ginger, and cook for another minute until fragrant.
Add the chopped tomatoes and green bell pepper to the pot.
Stir in the ground cumin and ground coriander.
Cook for about 5-7 minutes, until the tomatoes have softened and the mixture is well combined.
Add the peeled and chopped green bananas (matoke) to the pot.
Return the browned meat to the pot if using.
Pour in the beef or vegetable broth, stirring to combine.
Bring the mixture to a gentle boil.
Reduce the heat to low, cover the pot, and let the katogo simmer for about 30-40 minutes, or until the matoke and meat (if using) are tender.
Season with salt and black pepper to taste.
Transfer the katogo to a serving dish.
Garnish with fresh cilantro or parsley if desired.
Enjoy your meal!