Combine the quarters of 1 of the onions, 2 of the garlic cloves, the parsley leaves, 1 teaspoon sea salt and freshly ground pepper in a mortar and pestle or a food processor and muddle or pulse to chop until all the ingredients have processed into a green mush, about 3 minutes. Transfer the mixture to a medium bowl.
Working in batches if necessary, place the snapper in the same mortar or food processor used for the parsley. Use the pestle to pound the fish or the food processor to pulse the fish to a malleable texture. Add the fish to the bowl with the parsley mixture and mix well using your hands. Using a tablespoon, form the mixture into round balls called "bantu" and set aside.
Rinse the mortar and pestle or food processor and add the remaining onion quarters, garlic cloves, 2 teaspoons salt and the green and red bell peppers and muddle until the ingredients are crushed, about 3 minutes in a mortar and pestle or 20 seconds in a food processor. This is called "knokoss." Place in a medium bowl and set aside.
Heat the oil in a 4-quart Dutch oven over medium-high heat. Fry the bantu in batches until browned, about 2 minutes per side. When all the bantu has been browned, transfer to a medium bowl or plate and set aside.
Saute the knokoss in the same Dutch oven until soft and translucent, 3 to 5 minutes. Stir in the diced tomatoes, tomato paste and bouillon seasoning and cook for 2 minutes. Stir in 8 cups water and the bay leaf, bring to a simmer and let cook for 10 minutes.
Stir in the peanut butter until fully incorporated; the stew should turn a beige color and start to thicken. Stir until the stew starts to boil, then cover and turn the heat to medium-high. Cook for 30 minutes, stirring gently every 10 minutes.
Add the sweet potatoes, carrots, and Scotch bonnet chile. Check for seasoning; if more salt is required add the soy sauce. Give it a big stir, cover and simmer for another 10 minutes.
Carefully add the bantu and reduce the heat to low. Cover and let simmer for 5 to 10 minutes; the stew is done when a reddish peanut oil appears on top of the surface. Do not stir the oil to incorporate, simply turn off the stew and carefully remove the Scotch bonnet.
Serve over rice or foufou.
Foufou is made from pounding boiled starchy foods like plantains into large balls that are often served with stews.