01 - Preheat oven to 375°F. Lightly grease an 8x8-inch baking dish with olive oil or butter.
02 - In a large bowl, toss sweet potatoes and red onion with a pinch of salt and pepper. Evenly spread the mixture in the prepared dish.
03 - Bake sweet potatoes and onion for 20 minutes until beginning to soften.
04 - Remove dish from oven and distribute diced mango over the roasted sweet potato mixture.
05 - Whisk eggs, milk, cumin, smoked paprika, 1/2 teaspoon salt, and 1/4 teaspoon pepper in a mixing bowl. Stir in shredded cheese, if desired.
06 - Pour egg mixture evenly over the vegetables and mango in the baking dish.
07 - Return dish to oven and bake for 20 minutes until eggs are set and the surface is lightly golden.
08 - Remove dish from oven, let cool for 5 minutes, then sprinkle with chopped cilantro or parsley.
09 - Slice into portions and present warm.