Blackstone Ahi Tuna (Seared Tuna on the Flat Top)

Name: Blackstone Seared Ahi Tuna
Prep time: 5 min
Cook time: 4 min
Total time: 9 min
Yield: 2–4 servings
Cuisine: Asian-American
Ingredients: 2 ahi tuna steaks (6–8 oz each, sushi-grade); 2 tbsp avocado oil; ¼ cup sesame seeds (white, black, or mixed); 1 tsp coarse salt; 1 tsp cracked black pepper; 3 tbsp soy sauce; 1 tbsp sesame oil; 1 tbsp rice vinegar; 1 tsp grated ginger

Seared ahi tuna is one of the best things to cook on a Blackstone griddle. The technique is simple: extremely high heat, a sesame or pepper crust, 60–90 seconds per side, and you’re done. The Blackstone’s large steel surface gets hotter than most home stovetops and sears the tuna instantly while leaving the center raw to rare — exactly where sashimi-grade tuna should be.

Use sushi-grade or sashimi-grade tuna. This is not a dish where the grade of fish doesn’t matter.

Prep time: 5 minutes · Cook time: 3–4 minutes · Serves: 2–4

Griddle temperature: 450–500°F (maximum heat)

Ingredients

For the tuna:

2 ahi tuna steaks (6–8 oz each, at least 1 inch thick), sushi-grade
2 tbsp avocado oil (high smoke point)
¼ cup sesame seeds (white, black, or mixed)
1 tsp coarse salt
1 tsp cracked black pepper
Optional: 1 tsp wasabi powder mixed into the crust

Dipping sauce:

3 tbsp soy sauce or tamari
1 tbsp sesame oil
1 tbsp rice vinegar
1 tsp ginger, grated
1 tsp honey
1 green onion, sliced thin
Pinch of red pepper flakes

Instructions

Step 1: Make the dipping sauce

Whisk together soy sauce, sesame oil, rice vinegar, ginger, honey, and green onion. Set aside.

Step 2: Prep the tuna

Pat tuna steaks completely dry with paper towels — moisture prevents searing. Brush lightly with avocado oil. Press sesame seeds, salt, and pepper firmly onto all four sides of each steak.

Step 3: Get the griddle scorching hot

Crank the Blackstone to maximum heat. Let it preheat 5–7 minutes until the surface exceeds 450°F. This is a restaurant-quality sear that requires restaurant-level heat.

Step 4: Sear — 60–90 seconds per side

Add a thin film of avocado oil to the hottest zone. Place the tuna steaks down and do not touch them. Sear for 60–90 seconds — you’ll see a white line of cooked tuna creeping up the sides. Flip. Sear 60–90 seconds on the second side.

Step 5: Sear the edges

Stand the tuna on each narrow edge for 15–20 seconds to sear. This seals the crust all the way around.

Step 6: Rest briefly and slice

Rest for 1–2 minutes. Slice against the grain into ½-inch medallions. The center should be ruby red to deep pink — raw to rare. Serve immediately with the dipping sauce.

Tips

Maximum heat only. Ahi tuna searing is a race against time — the crust needs to form before the interior heats above rare. Lower temperatures cook the center through before the sesame crust sets. Don’t try this at medium heat.

Sushi-grade fish. Only sushi-grade or sashimi-grade ahi tuna is appropriate for a rare center. Ask your fishmonger specifically for sashimi-grade yellowfin or bigeye tuna.

Dry the fish. Any moisture on the surface creates steam that prevents searing. Paper towels, then pat again. The surface should look matte, not shiny.

Don’t move it. The sesame crust sticks to the griddle for the first 20–30 seconds as it sears. It will release naturally once the crust sets — don’t force it.

More flat-top recipes: Blackstone Fish Recipes · Blackstone Dinner Ideas · Blackstone Asian Recipes

Frequently Asked Questions

What temperature do you cook ahi tuna on a Blackstone griddle?

450–500°F — the hottest your griddle will go. Ahi tuna is seared for only 60–90 seconds per side and served rare in the center. Maximum heat is essential for developing a seared crust before the interior heats above rare.

How long do you cook ahi tuna on a Blackstone?

60–90 seconds per side — 3–4 minutes maximum. Ahi tuna is intentionally served rare in the center. If you want well-done tuna, cook 2–3 minutes per side, but the texture and flavor will be significantly inferior to rare.

How do you know when seared ahi tuna is done?

Watch the sides — you’ll see a white cooked line creeping up from the bottom as you sear. For rare: the white line should extend about ¼ inch up from each side. The center should remain ruby red when sliced. At 90 seconds per side on maximum heat, this is typically achieved.

Can you use frozen ahi tuna for searing?

Yes, if it was frozen properly (sashimi-grade fish is often flash-frozen at sea). Thaw completely in the refrigerator overnight, pat very dry, and bring to room temperature for 20 minutes before searing.