Make the banku: In a large heavy pot, whisk together the Fermented Corn Dough and the Fermented Cassava Dough with about 3 cups of Water until you have a smooth, lump-free batter; season with a pinch of Salt.
Cook the mixture over medium heat, stirring constantly with a wooden spoon; as it thickens, fold and press the dough against the pot until it becomes glossy and elastic (10–15 minutes). If it gets too stiff, add a little more Water and continue working it until the texture is like a soft dumpling. Once done, cover and keep warm.
Prepare the fish: Rinse and pat dry the Tilapia and make a few shallow diagonal cuts in the skin so flavors penetrate. Season both sides with a little Salt and freshly ground Ground Black Pepper.
Make a simple marinade/paste by combining minced Garlic, grated Ginger, finely chopped Onion and a small amount of finely minced Scotch Bonnet Pepper with a splash of Lemon Juice. Rub this mixture all over the fish and let it rest for 15–30 minutes.
Heat 2–3 tablespoons of Vegetable Oil in a large skillet over medium-high heat. Fry the marinated Tilapia 4–6 minutes per side (depending on thickness) until the skin is crisp and the flesh flakes easily. Transfer to a plate and keep warm.
Using the same skillet, lower the heat and sauté another sliced Onion in the pan drippings until translucent. Add any remaining minced Garlic, Ginger and Scotch Bonnet Pepper, then stir in chopped Tomato.
Simmer the tomato mixture until it breaks down and becomes a saucy consistency, about 6–8 minutes; season with Salt and Ground Black Pepper to taste, and add a splash of Water if it needs loosening.
Finish the sauce with a squeeze of fresh Lemon (or more Lemon Juice if you prefer) to brighten the flavors, then remove from heat.
To serve: shape the banku into balls and place on plates with the Tilapia. Spoon the spicy tomato-pepper sauce over the fish and offer extra lemon wedges for squeezing. Eat by hand or with a fork—scoop a bit of banku, dip into the sauce, and enjoy.
