In a medium bowl, toss together the mango, avocado, red onion, cilantro and lime juice. Cover while preparing halibut.
Preheat oven to 350°F. In small bowl, combine the light brown sugar, paprika, cumin, salt, garlic powder, thyme, black pepper and cayenne pepper. Rub the seasoning into the fish, making sure it's entirely coated.
Heat 1 tablespoon olive oil over medium-high heat in large skillet. Add fish to skillet and cook for 2 minutes per side or until blackened. Transfer to the oven and bake for 5 minutes or until cooked through.
Thank you Ava Koo for passing along this awesome recipe!