Black Sesame Tuna Wasabi Mayo

The first time I seared tuna with a black sesame crust, I was trying to impress someone who claimed they didn't eat fish. The kitchen filled with this nutty, toasted aroma that made them lean against the counter asking what I was making. Three minutes later, watching them take that first bite and close their eyes was worth every moment spent hunting down sushi-grade tuna at the fishmonger. This dish has that magic where it looks far more complicated than it actually is, which somehow makes it even better when you pull it off.

I made this for my neighbor last summer when she brought over tomatoes from her garden. She'd been talking about wanting to eat healthier, and I thought something elegant but simple might appeal to her. She sat at my kitchen counter with a glass of wine while I seared the tuna, and the whole thing took less time than it took us to catch up. She asked for the recipe that same night, and now I see her at the farmers market comparing tuna steaks the way other people compare avocados.

Ingredients

• Sushi-grade tuna steaks (6 oz each, about 1 inch thick): This is non-negotiable—ask your fishmonger specifically for sushi-grade, which means it's been handled and stored to eat raw. I learned this lesson the hard way by assuming fresh meant suitable, and it doesn't.
• Black sesame seeds (1/2 cup, toasted): The toasting is key, bringing out their nutty depth and ensuring they stick to the tuna when pressed. Buy them already toasted if you can, or toast them yourself in a dry pan for about 2 minutes, shaking often.
• White sesame seeds (1/4 cup, optional): These add visual contrast and a milder flavor note, though the black alone is stunning if that's all you have.
• Soy sauce (1 tablespoon): This seasons the tuna before the crust and adds umami depth that plays beautifully against the wasabi heat.
• Sesame oil (1 teaspoon): Use the dark, toasted kind—it's aromatic and adds richness without overwhelming the delicate fish.
• Salt and freshly ground black pepper: Season lightly, remembering the soy sauce already contributes saltiness.
• Mayonnaise (1/4 cup): This is your base for wasabi mayo and helps balance the heat while adding richness.
• Wasabi paste (1-2 teaspoons): Start with less and build up; it's potent and keeps developing heat as it sits.
• Rice vinegar (1 teaspoon): This brightens the mayo and prevents it from feeling heavy.
• Lemon juice (1 teaspoon): Adds acidity and freshness that ties the whole thing together.
• Scallions, pickled ginger, lemon wedges (for garnish): These aren't just decoration—they're palate cleansers and flavor additions that make each bite interesting.

Instructions

Prep ingredients easily by chopping vegetables, slicing meats, and serving dishes neatly during everyday cooking.

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Prepare your tuna:

Pat the steaks dry with paper towels—moisture is the enemy of a good crust. Brush all sides lightly with soy sauce and sesame oil, then season with just a pinch of salt and pepper since the soy brings saltiness already.

Coat with sesame seeds:

Pour the black (and white if using) sesame seeds onto a shallow plate and press each tuna steak firmly into them, turning to coat all four sides evenly. Don't be shy—you want a proper crust, not a light sprinkling.

Get your pan smoking hot:

Heat a non-stick or cast-iron skillet over high heat until it's genuinely hot, at least 2-3 minutes. Add just enough oil to coat the bottom—you want searing heat, not a bath.

Sear the tuna fast:

Place the coated steaks in the pan and listen for that aggressive sizzle. Sear for 30-45 seconds per side, touching them only once per side, until the sesame crust turns golden brown and the outside feels firm but the center stays soft when you press it gently.

Rest and make the mayo:

Remove the tuna to a clean plate and let it rest for just a minute while you whisk together mayonnaise, wasabi paste, rice vinegar, and lemon juice in a small bowl. Taste and adjust the wasabi—it should make you slightly nervous but in a good way.

Slice against the grain:

Cut each tuna steak into 1/2-inch slices using a sharp knife, working with confidence so the knife glides through rather than dragging. The slices should show a beautiful rare center with just the golden crust around the edges.

Plate and serve:

Arrange the slices on your plates, drizzle generously with wasabi mayo, and scatter scallions and pickled ginger over top. Add lemon wedges on the side for squeezing over at the last moment.

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There's this moment right when the tuna hits the hot pan where the sound changes everything—that sharp, urgent sizzle that tells you something special is happening. My brother claims he can smell when I'm making this from three houses away, which says everything about how those toasted sesame seeds fill a space with warmth and intention.

Sourcing Your Tuna Matters More Than You Think

I've learned that where you buy your tuna changes this dish entirely. The fishmonger at my local market knows I make this, and he sets aside the best-looking steaks from his sushi-grade selection. He once told me that most tuna is frozen specifically for safety, then thawed—asking for sushi-grade means you're getting fish that's been handled with extra care and can be eaten raw. Building a relationship with someone who cares about their fish elevates everything you make with it.

The Wasabi Mayo Is Where Personality Lives

This isn't just a condiment—it's the bridge that brings everything together. The creaminess of the mayo tempers the heat of wasabi while the rice vinegar and lemon juice keep it from feeling heavy or one-note. I once made it too spicy trying to impress someone, and they actually appreciated the challenge, but the magic is in that balance where you feel the heat building slowly rather than getting knocked over immediately. Trust your palate when adjusting the wasabi; you can always add more, but you can't take it back.

Why 30 Seconds Per Side Changes Everything

The entire success of this dish hinges on that brief, aggressive sear. You're locking in the crust while keeping the inside completely raw, which is the whole point. I've watched people hesitate at the pan, worried they're not cooking it enough, and end up with a steak that's barely warm inside and somehow less appealing. Your job isn't to cook the tuna—it's to add texture and flavor to something that's already perfect eaten raw.

• Use a timer because eyeballing timing on something this quick is how you learn expensive lessons.
• Let your pan get hot enough that you feel nervous—if it looks smoking, that's exactly right.
• Trust that rare is what makes this dish worth making in the first place.

Chop vegetables, slice meats, and prep ingredients easily for everyday cooking and homemade recipes.

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This is the dish I make when I want to feel like I've done something impressive without spending hours in the kitchen. It's become my favorite way to feed people who think they're hungry for something complicated, then discover simple perfection is what they actually wanted.

Recipe Questions & Answers

→ What type of tuna is best for this dish?

Sushi-grade tuna steaks are ideal for the freshest taste and safe consumption when served rare.

→ How do I achieve the perfect crust on the tuna?

Press the tuna into toasted black sesame seeds evenly, then sear quickly on high heat to form a golden crust while keeping the interior rare.

→ Can I adjust the spice level of the wasabi mayo?

Yes, vary the amount of wasabi paste in the mayo to suit your preferred heat intensity.

→ Is there an alternative to regular mayonnaise?

Dairy-free or vegan mayonnaise can be used to maintain the creamy texture while fitting dietary preferences.

→ What garnishes complement the dish?

Thinly sliced scallions, pickled ginger, and lemon wedges enhance freshness and add layers of flavor.

→ How should I slice the tuna for serving?

Slice the seared tuna against the grain into half-inch thick pieces to ensure tenderness.