In a large ovenproof skillet, heat the olive oil over medium heat. Add the red onion and bell pepper, and sauté for a couple of minutes until the onion softens.

Stir in the sweet potato pieces. Cook for about 5 minutes, stirring occasionally, until they begin to soften.

Mix in the garlic and jalapeño, and cook for an additional minute until fragrant. sprinkle in the smoked paprika, cumin, oregano, salt, and black pepper. Stir for about 30 seconds to let the spices bloom.

Preheat your oven to to 375°F (190°C).

Pour in the diced tomatoes, and add the black beans and sweetcorn. Stir well to combine. Bring the mixture to a gentle simmer, and cook for 10–15 minutes, stirring occasionally, until the sweet potatoes are tender. If the mixture appears too dry, add a splash of water.

Evenly distribute the grated cheddar cheese over the top of the mixture. Transfer the skillet to the preheated oven and bake for about 10 minutes, or until the cheese has melted and developed a light golden color.

Remove the casserole from the oven and let it rest for a couple of minutes. Sprinkle fresh cilantro, and add slices of avocado and chopped scallions just before serving.