This Vietnamese-style tuna steak is seared in a hot skillet after a brief marinade of fish sauce, lime, lemongrass, garlic, and ginger. The savory, citrusy coating gives the fish plenty of flavor, while a fresh lime-and-fish-sauce dip and herbs make it a bright, satisfying meal; this is a home-cooking interpretation, not a claim that there is one definitive Vietnamese version.
Ingredients
- 4 tuna steaks, about 1 inch (2.5 cm) thick and 6 oz (170 g) each, for 1½ lb (680 g) total
- 2 tbsp (30 ml) fish sauce, divided
- 2 tbsp (30 ml) fresh lime juice, divided, plus lime wedges for serving
- 1 tbsp (15 ml) neutral oil, such as canola or avocado oil
- 1 tbsp (6 g) finely minced fresh lemongrass, tender inner part only
- 2 garlic cloves (6 g), finely grated or minced
- 1 tbsp (6 g) finely grated fresh ginger
- 1 tsp (4 g) granulated sugar, divided
- ¼ tsp (0.5 g) freshly ground black pepper
- 2 tbsp (30 ml) warm water, for the dipping sauce
- 1 small red Thai chile (about 5 g), thinly sliced, or ½ tsp (1 g) red pepper flakes, optional
- ¼ cup (10 g) roughly chopped cilantro leaves, for serving
- 2 tbsp (8 g) thinly sliced scallions, for serving
- ½ tsp (2 g) kosher salt, only if needed after tasting; fish sauce is already salty
Instructions
- Make the marinade. In a shallow dish, stir together 1 tbsp (15 ml) of the fish sauce, 1 tbsp (15 ml) of the lime juice, the oil, lemongrass, garlic, ginger, ½ tsp (2 g) of the sugar, and the black pepper. Pat the tuna dry with paper towels so the marinade clings and the steaks can brown. Add the tuna and turn each piece to coat. Cover and refrigerate for 15 minutes, turning once halfway through. Avoid a much longer marinade: the salt can make the surface firm and the lime can soften it.
- Mix the dipping sauce while the fish marinates. In a small bowl, combine the remaining 1 tbsp (15 ml) fish sauce, 1 tbsp (15 ml) lime juice, 2 tbsp (30 ml) warm water, and remaining ½ tsp (2 g) sugar. Stir until the sugar dissolves, then taste. Add the sliced chile if you want heat. The sauce should taste lively and balanced, not overwhelmingly salty; add a little more water or lime to adjust it. Keep this clean sauce separate from the raw-fish marinade.
- Heat the skillet. Take the tuna out of the refrigerator and lift each steak from the marinade, letting excess drip back into the dish. Discard the marinade; it has touched raw fish and should not be served. Heat a large heavy skillet over medium-high heat until hot. If the skillet is not large enough to hold two steaks with space around them, plan to cook in smaller batches rather than crowding the pan.
- Sear the tuna. Add two steaks to the dry, hot skillet and cook for about 4 minutes on the first side, then turn and cook for about 4 minutes on the second side. Use tongs to briefly sear the edges if they are thick. Transfer the first batch to a clean plate and repeat with the remaining steaks. Check the center of each steak with a food thermometer inserted through the side; USDA FSIS lists 145°F (63°C) as the safe minimum internal temperature for fish. If a steak has not reached that temperature, continue cooking in short increments and check again. The center will be fully cooked at this temperature, rather than rare.
- Rest and finish. Let the cooked steaks rest on the clean plate for 3 minutes. Spoon a little of the dipping sauce over each steak, then scatter cilantro and scallions on top. Serve the remaining sauce and lime wedges at the table. If the skillet leaves browned lemongrass or garlic bits that are close to burning, wipe them out between batches so the second round does not taste bitter.
Tips
- Choose evenly thick steaks. Tuna steaks around 1 inch (2.5 cm) thick cook more evenly than very thin pieces and are easier to check with a thermometer. If your steaks are thinner, begin checking their temperature sooner; if they are thicker, they may need additional time. The thermometer reading, not the clock or color alone, determines when they have reached the safe minimum.
- Use the tender part of the lemongrass. Peel away dry outer layers, trim the woody base, and mince the pale inner stalk very finely. Tough pieces can stay stringy after cooking. If fresh lemongrass is unavailable, substitute 1 tsp (5 ml) lemongrass paste; it may be saltier, so taste the dipping sauce before adding any extra salt. A little extra lime zest can provide a citrusy note, but it will not reproduce lemongrass’s distinctive aroma.
- Substitute fish sauce thoughtfully. Fish sauce supplies the marinade’s salty, savory depth. If you cannot use it, replace it with 1½ tbsp (22 ml) low-sodium soy sauce and add ½ tsp (2.5 ml) lime juice. The result will be less traditionally Vietnamese in flavor and more soy-forward. Coconut aminos are another option, but they are sweeter and milder, so adjust the sugar in the dipping sauce to taste.
- Prevent sticking and overcooking. Dry the fish before marinating, preheat the pan, and leave space between steaks. A thin film of oil can be added if your skillet is not well seasoned, but too much oil makes the marinade scorch and splatter. Do not judge doneness by whether the middle looks pink: tuna color varies, and a thermometer provides a reliable safety check.
Serving Suggestions
Serve each steak with steamed jasmine rice or broken rice to catch the lime-fish-sauce dressing. For a lighter plate, pair it with rice vermicelli, shredded lettuce, cucumber, bean sprouts, and fresh herbs; diners can cut or flake the cooked tuna and build their own bowls. A quick side of sautéed greens, such as water spinach, bok choy, or spinach, works well because its mild flavor does not compete with the lemongrass.
For a family-style meal, put the tuna on a platter with the cilantro, scallions, lime wedges, and dipping sauce on the side. Add sliced cucumber or lightly pickled carrots and daikon for crunch and acidity. If serving the fish with noodles, keep the sauce in a small bowl so each person can add just enough rather than soaking the whole plate. These accompaniments are suggestions, not required parts of the recipe.
Variations
Make it less spicy: Leave out the chile or pepper flakes. The dipping sauce remains bright and savory without them. For more heat, add a second small chile or serve sliced chile separately so everyone can adjust their portion.
Add a little sweetness: For a rounder, slightly sweeter flavor, replace the teaspoon of sugar in the marinade with 1 tsp (7 g) honey. Honey browns quickly, so watch the pan closely and lower the heat slightly if the garlic or fish surface darkens before the center reaches temperature.
Use another firm fish: Thick swordfish or mahi-mahi steaks can be prepared with the same marinade and cooked to 145°F (63°C), checking each piece with a thermometer. Their texture and flavor differ from tuna, so use the timing as a guide rather than a guarantee. Thin white-fish fillets are more delicate and can break when turned, so they are not the easiest one-for-one swap in this skillet method.
Turn it into a rice bowl: Slice the cooked tuna across the grain and arrange it over rice with cucumber, herbs, and a spoonful of dipping sauce. Keep the fish fully cooked as directed. This is a convenient way to serve smaller portions or use up cooked tuna, and the fresh vegetables add contrast without requiring a separate elaborate side dish.
Storage and Reheating
Refrigerate leftover cooked tuna within 2 hours of cooking, in a covered, shallow container. It keeps for 3 to 4 days in a refrigerator at 40°F (4°C) or colder. Store the dipping sauce separately and use it within 3 to 4 days as well; discard it if it has been sitting out with the meal for more than 2 hours. Do not store the uncooked fish in its marinade for later cooking beyond the brief 15-minute marinating time in this recipe.
For the most even reheating, place a portion in a covered skillet with a teaspoon of water and warm it over low heat, turning once. You can also microwave it in short intervals, covered, until the center reaches 165°F (74°C), the USDA FSIS safe temperature for reheated leftovers. Reheating tuna to that temperature can make it drier and firmer than freshly cooked fish, so add a little fresh lime or dipping sauce after warming. Cooked tuna can be frozen in a sealed freezer-safe container for about 2 to 3 months for best quality; thaw it in the refrigerator and reheat safely.
Frequently Asked Questions
Can I make this Vietnamese tuna steak ahead?
Mix the dipping sauce up to a day ahead and refrigerate it in a covered container. You can also mince the lemongrass, garlic, and ginger earlier in the day. For best texture, marinate the tuna for only 15 minutes just before cooking rather than leaving it in the lime-and-fish-sauce mixture overnight.
Can I cook the tuna on a grill?
Yes. Heat a clean, lightly oiled grill to medium-high and cook the steaks with the same thermometer target of 145°F (63°C). The exact timing depends on the grill, steak thickness, and how cold the fish is when it goes on. Turn with a thin spatula or tongs once the first side releases easily, and check the center of every steak rather than relying on grill marks.
Why is my tuna sticking to the pan?
The skillet may not have been hot enough, or the fish may have been wet from excess marinade. Pat the tuna dry before marinating, let excess liquid drip off, and allow the pan to heat before adding the steaks. Do not try to pull the fish up immediately; a well-seared surface often releases more easily once it has browned.
Can I use bottled lime juice?
Fresh lime juice gives the dipping sauce a brighter, less flat flavor, but bottled juice can work in a pinch. Start with the listed amount, taste, and adjust with a little water or sugar if it seems unusually sharp. If fresh lime is available, use its zest sparingly in the marinade for extra fragrance, taking care not to grate the bitter white pith.
How do I know the tuna is done without cutting it open?
Use an instant-read food thermometer inserted into the thickest part from the side. Cook each steak to 145°F (63°C), the USDA FSIS safe minimum for fish. Color and firmness can vary by tuna type and cooking conditions, so they are not dependable substitutes for a temperature reading.
Is the marinade also the dipping sauce?
No. Keep the dipping sauce separate and clean, as directed. The marinade has contacted raw tuna and must be discarded; do not pour it over cooked fish or use it as a sauce unless it is separately brought to a full boil. Making a separate dipping sauce takes only a minute and keeps the serving condiment ready to use.
Related
- Vietnamese Pickled Vegetables (Đồ Chua) Recipe
- 1 Gallon Pho Broth Recipe, Vietnamese Style
- Vietnamese Lemongrass Chicken: A Bright, Savory Dinner
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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes
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