Vegetarian Burritos

Name: Vegetarian Burritos
Ingredients: 1 green bell pepper, sliced into thin strips; 1 red bell pepper, sliced into thin strips; 1 white onion, sliced into this strips; 15 ounces refried beans; 15 ounces black beans, drained; 1⁄2 cup frozen corn; 1 tablespoon taco seasoning; 1⁄4 cup sour cream; 2 cups iceberg lettuce, chopped; 2 roma tomatoes, seeded and chopped; 1 tablespoon olive oil; 1 teaspoon kosher salt; 1⁄4 teaspoon black pepper; 1 tablespoon unsalted butter; 1⁄3 cup water; 6 burrito-size flour tortillas; 1 cup monterey jack and cheddar cheese blend, blend shredded