To prepare the matooke, place 2 cups of water and the plantains in a pot and simmer until tender, about 25 minutes. Drain and then mash. Add water if needed to reach desired consistency.
To prepare the peanut sauce, chop the tomato and onion. Add them with the remaining 2 cups water to a saucepan over medium-high heat and bring to a boil.
Stir in the peanut butter and spices. Let the mixture simmer, stirring continuously until it thickens.
Pour over the prepared matooke.