Black Bean Plantain Chili

Name: Black Bean Plantain Chili
Ingredients: 1 tablespoon vegetable oil; 1 medium onion, (diced); 1 red bell pepper, (diced); 3 garlic cloves, (minced); 2 (14 ounce) cans black beans, drained and rinsed; 1 (14 ounce) can crushed tomatoes; 1 (14 ounce) can diced tomatoes; 1 tablespoon chili powder; 1 1/2 teaspoons ground cumin; 1 teaspoon smoked paprika; 1/2 teaspoon ancho chili powder; 2 ripe plantains, (yellow with plenty of brown spots, peeled and cut into 1 inch chunks); salt and pepper to taste; fresh cilantro; chopped scallions; avocado slices