Place the eggplant and plantain in a baking dish and drizzle with olive oil. Bake for 25 minutes. Meanwhile, in a medium skillet, heat the vegetable oil over medium heat. Add the tomato, onion, garlic, salt and pepper and cook stirring occasionally for 10 minutes. Set aside.
Place the eggplant and plantains in a food processor until they are combined, being careful not to over-process. The two ingredients only need to be blended together, not completely pureed.
Transfer eggplant and plantain mixture to a bowl. Add the guiso or tomato mixture and mozzarella cheese and mix well. Spoon to a serving bowl.