01 - Preheat oven to 375°F. Lightly grease an 8x8-inch baking dish with olive oil or butter.
02 - In a large mixing bowl, combine diced sweet potatoes and red onion with a pinch of salt and black pepper. Evenly distribute the mixture in the baking dish.
03 - Bake the sweet potato and onion mixture for 20 minutes, until just beginning to soften.
04 - Remove baking dish from oven and sprinkle diced mango evenly across the vegetables.
05 - In a separate bowl, whisk together the eggs, milk, ground cumin, smoked paprika, salt, and pepper. If using, incorporate the shredded cheese.
06 - Pour the whisked egg mixture over the vegetables and mango. Return dish to oven and bake for an additional 20 minutes, until the eggs are set and the top is lightly golden.
07 - Remove dish from oven. Allow to cool for 5 minutes, then add chopped cilantro or parsley before slicing and serving warm.