This tuna steak stir fry with quinoa is a clean, colorful dish that brings together fresh tuna, crisp vegetables, and a light soy-lime and sesame sauce.

Ingredient Notes & Substitutions
- Tuna Steaks: Look for sushi-grade tuna that’s firm to the touch and has a vivid, ruby-red color throughout. The surface should look moist and glossy, not dull, brownish, or grey. If you’re using frozen tuna, make sure it’s fully thawed and patted dry
- Soy Sauce: Adds depth to both the marinade and stir-fry sauce. Use low-sodium soy sauce if you’re watching salt levels, or tamari for a gluten-free option.
- Lime Juice: Always use freshly squeezed lime juice for brightness and acidity. Bottled juice lacks the same fresh flavor.
- Sesame Oil: Use toasted sesame oil for its rich, nutty aroma.
- Oil: Use a neutral, high smoke point oil like vegetable oil, avocado oil, canola oil, or grapeseed oil. These are ideal for both searing the tuna and stir-frying the vegetables.
- Garlic & Ginger: Use freshly minced garlic and ginger for the most vibrant flavor.
- Red Onion: Adds mild sweetness and texture. You can substitute with shallots or yellow onion if preferred.
- Bell Pepper: Brings color and crunch. Use any color you like—red, yellow, or orange peppers all work well.
- Snap Peas: Add freshness and a crisp bite. Green beans or snow peas can be used if snap peas aren’t available.
- Spinach: Wilts down quickly and adds nutrients and color. You can also use baby kale.
- Quinoa: I used cooked quinoa as the base but you can also use rice, noodles or cauliflower rice.
- Chili or Chili Flakes: Adjust the spice level to suit your taste. For a milder dish, leave it out.
- Garnish (Optional): Garnish with cilantro or sliced spring onions for extra color and freshness.
Chef Tips
- Keep the tuna cold until cooking – Buy your tuna last when shopping and refrigerate it as soon as you get home. Use a cooler bag with cooling packs if you’re out for a while.
- Marinate the tuna for at least 30 minutes – This gives the soy sauce time to marinate the tuna.
- Use a hot, heavy-bottomed pan for searing – Cast iron or stainless steel works best. Preheat the pan well before adding the tuna to ensure a golden, even crust.
- Stir-fry the vegetables quickly over high heat – Keep them crisp and vibrant by moving them around the wok and cooking in batches if needed.
Tuna Steak Cooking Temperatures
Tuna is usually best served rare to medium-rare. Use a food thermometer to check internal temperature if needed.
- Rare: 115°F to 120°F (46°C to 49°C)
- Medium-rare: 120°F to 130°F (49°C to 54°C)
- Medium: 130°F to 140°F (54°C to 60°C)
- Well done: 145°F+ (63°C+)
Storage and Leftovers
Store the tuna, quinoa, and vegetables together in an airtight container once cooled. Refrigerate for up to 2 days.
To reheat, microwave covered on medium power until just hot throughout. Avoid overheating, as tuna can dry out. If you prefer, you can remove the tuna and reheat it separately in a skillet over medium-low heat
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Seared Tuna with Quinoa & Stir-Fried Vegetables
This tuna steak stir fry with quinoa is a clean, colorful dish that brings together fresh tuna, crisp vegetables, and a light soy-lime and sesame sauce.
Equipment
- 2 Mixing Bowls
- Medium Sauté Pan
Ingredients
Tuna Marinade:
- 2 fillets tuna steaks (about 5 oz / 140 g each)
- 2 teaspoons light soy sauce
Stir-Fry Sauce:
- 3 tablespoons light soy sauce
- 1 lime
- 1 teaspoon sesame oil
Stir-Fry Base:
- vegetable oil
- 2 garlic cloves minced
- 1 teaspoon fresh ginger minced
- ½ red onion sliced
- 1 mixed bell pepper roughly sliced
- 3 oz snap peas
- 3 oz spinach
- 1 chilies sliced (or chili flakes, to taste)
- 12 oz cooked quinoa
Garnish (optional):
- Fresh cilantro optional
- Sliced spring onions optional
Instructions
Marinate the Tuna:
- In a mixing bowl or zip-top bag, combine the tuna steaks with soy sauce.
- Cover and marinate in the refrigerator for at least 30 minutes.
Prepare the Stir-Fry Sauce:
- In a small mixing bowl, whisk together the soy sauce, lime juice, and sesame oil. Set aside.
Make the Vegetable Stir-Fry:
- Heat a large wok over medium-high heat.
- Add vegetable oil, then stir-fry the garlic and ginger for 30 seconds, until fragrant.
- Add the red onion, bell pepper, and snap peas. Stir-fry for 3 to 4 minutes. If the wok gets too hot, add a splash of water.
- Add the spinach, chilies (or chili flakes), and the prepared stir-fry sauce. Stir constantly until the spinach is wilted.
- Reduce the heat to medium-low. Add the cooked quinoa and mix well. Stir regularly to heat through while you sear the tuna.
Sear the Tuna Steaks:
- Heat a medium sauté pan over high heat.
- Once the pan is hot, add a small amount of vegetable oil.
- Sear the tuna steaks on each side until your desired cooking temperature. For doneness temperatures, see notes.
Assemble and Serve:
- Divide the quinoa and vegetable stir-fry between plates.
- Top each portion with a seared tuna steak.
- Garnish with fresh cilantro and sliced spring onions.
Notes
-
Tuna Cooking Temperature Guide: Use a food thermometer to check internal temperature if needed:
- Rare: 115°F to 120°F (46°C to 49°C)
- Medium-rare: 120°F to 130°F (49°C to 54°C)
- Medium: 130°F to 140°F (54°C to 60°C)
- Well done: 145°F+ (63°C+)
Nutrition
Calories: 513kcalCarbohydrates: 56gProtein: 44gFat: 12gSaturated Fat: 2gCholesterol: 46mgSodium: 1759mgPotassium: 781mgFiber: 9gSugar: 7gVitamin A: 7056IUVitamin C: 1125mgCalcium: 100mgIron: 4mg
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