Preheat oven to 450 degrees.
Begin risotto by sautéing garlic and onion in olive oil and butter over medium heat in medium-sized pot.
Add in rice, stir occasionally and let toast 5 minutes. Slowly stir in broth 1 c at a time, not adding next cup until all of broth is absorbed. You've added enough broth when rice is creamy and al-dente, or still has a little bit of bite.
Line jelly-roll pan with parchment paper. Add brussels sprouts, bacon, olive oil, and salt and pepper to pan, mix well, and roast about 20 minutes or until crispy.
Heat olive oil in fish pan over medium heat. Mix remaining ingredients in large bowl. When oil is hot, dredge mahi-mahi pieces in flour and cornmeal mixture, covering all sides. Gently lay in pan, it should immediately begin to sizzle.
Check after about 5 minutes to see if filets release easily and are crisp on the bottom. Flip when ready, repeat on all sides.
When ready to serve, mix parmesan into risotto, stir well. Ladle into bowl, top with crispy brussels sprouts, mahi-mahi, garnish with chives, cayenne, and freshly-ground black pepper.