In a large bowl, combine the chicken pieces (or beef/goat) with the ground cumin, ground coriander, ground paprika, ground turmeric, salt, and black pepper.
Mix well to coat the meat evenly with the spices.
In a large skillet, heat the vegetable oil over medium heat.
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 skillet.
Cook for about 5-7 minutes, until the tomatoes have softened and the mixture is well combined.
Add the spiced meat to the skillet and mix well with the vegetable mixture.
If using, stir in the coconut milk.
Cook for about 10 minutes, allowing the flavors to meld together. Remove from heat.
If using fresh banana leaves, pass them over an open flame or dip them in hot water to make them pliable and easier to fold without tearing.
Cut the banana leaves into large squares (about 12x12 inches or 30x30 cm).
Place a portion of the meat and vegetable mixture in the center of each banana leaf square.
Fold the edges of the banana leaf over the filling to create a secure parcel.
Tie the parcels with kitchen twine to keep them closed.
Arrange the parcels in a steamer basket.
Steam the parcels over boiling water for about 1.5 to 2 hours, or until the meat is tender and cooked through.
Remove the parcels from the steamer and let them cool slightly.
Carefully untie and open the banana leaves.
Transfer the luwombo to serving dishes.
Garnish with fresh cilantro or parsley if desired.
Enjoy your meal!