In a mixing bowl, combine balsamic glaze with cayenne pepper, paprika, and garlic powder to create a marinade. Add Ahi tuna steaks and coat well. Marinate for 10 to 30 minutes.

Preheat a cast iron skillet on medium-high, add high smoke-point oil, and let it shimmer (about 3–5 minutes).

Remove the tuna from the marinade and dry them. Sprinkle salt and pepper, then coat with blackened seasoning mix.

Place seasoned tuna in the hot skillet, cooking for 2–4 minutes on one side until a crust forms. Flip and cook for another 2–4 minutes. Aim for medium-rare.

Remove the tuna steaks and let them rest for 2-3 minutes on a cutting board.

Slice thinly against the grain and drizzle with reserved balsamic glaze. Serve with veggies or rice.