Baked tuna with a crispy celery topping and creamy mushroom filling transforms simple ingredients into a restaurant-worthy dish that’s surprisingly easy to master. The secret lies in the contrast—tender, flaky tuna beneath a golden celery crust, all blanketed in a velvety mushroom sauce that ties everything together.
I developed this recipe after years of experimenting with Japanese-style baked fish, and it’s now my go-to for pescatarian dinners that impress without fuss.
What makes this recipe stand out is the balance of textures and flavors: the celery topping adds a satisfying crunch, while the mushroom filling delivers deep umami richness that complements the tuna’s natural sweetness.
You’ll need just 15 minutes of prep time, followed by 20 minutes in the oven at 425°F, making it perfect for weeknight meals when you crave something special but don’t want to spend hours in the kitchen.
The result is a dish that looks elegant enough for a dinner party but comes together with minimal effort—crispy on top, creamy in the middle, and perfectly cooked tuna at the heart.
Serve it over steamed jasmine rice or with a side of roasted asparagus to round out the meal, and don’t forget a drizzle of soy-ginger sauce for that final touch of sophistication.
This recipe works equally well with fresh or frozen tuna, and the technique scales easily for leftovers or meal prep. Whether you’re cooking for two or feeding a crowd, the method stays consistent, ensuring every bite delivers that perfect harmony of textures and flavors. Let’s get started!
Ingredients for baked tuna
Fifteen minutes prep meets restaurant-quality textures—crispy celery crust, creamy mushroom filling, and perfectly cooked tuna.
| Ingredient | Amount | Notes |
|---|---|---|
| Fresh Tuna Steak 🐟 | 1 ½ lb | Sushi-grade, 1-inch thick slices |
| Celery Stalks 🥬 | 3 whole | Thinly sliced on mandoline (safety first!) |
| White Mushrooms 🍄 | 8 oz | Sliced thin, cremini or baby bella work too |
| Shallots 🧅 | 2 whole | Minced fine, or sub 2 tbsp onion powder |
| Garlic Cloves 🧄 | 3 cloves | Minced, fresh preferred for depth |
| Heavy Cream 🥛 | ½ cup | Full-fat for velvety texture (no substitutes) |
| Dijon Mustard 🍯 | 1 tbsp | High-quality, grainy preferred |
| Dry Sherry 🍷 | 2 tbsp | Or sub dry white wine (no sweetness) |
| Panko Breadcrumbs 🍞 | ½ cup | Japanese panko for extra crispiness |
| Extra-Virgin Olive Oil 🫒 | 2 tbsp | For brushing and crisping |
| Salt 🧂 | 1 ½ tsp | Kosher or sea salt, adjust to taste |
| Black Pepper 🌶️ | ½ tsp | Freshly cracked for best flavor |
| Fresh Parsley 🌿 | ¼ cup | Chopped, for garnish (optional) |
| Lemon Zest 🍋 | 1 tsp | Brightens the mushroom filling |
The tuna is your star, so sushi-grade quality is non-negotiable. Grab it from the seafood counter—ask for 1-inch thick slices (thinner cooks too fast). Whole Foods or Trader Joe’s carry pre-sliced packs if you’re short on time, but fresh-cut stays juicier. For the mushrooms, cremini or baby bella add deeper flavor than white, but use what’s on sale. The shallots? Freshly minced makes all the difference—no pre-minced jarred stuff here.
No sherry? Dry white wine or extra chicken broth works, but skip the sweet versions. Short on panko? Regular breadcrumbs toasted in the oven (400°F for 5 minutes) work in a pinch. The Dijon mustard is key—grainy types add texture, while smooth versions work for creaminess. For extra umami, add 1 tsp fish sauce or soy sauce to the mushroom filling. The celery topping can be prepped ahead—just store it dry in the fridge until baking.
This dish reheats beautifully—30 seconds in the microwave or 5 minutes at 350°F to restore crispiness. The mushroom filling keeps 3 days in the fridge (cover tightly), while the celery topping stays fresh 2 days if stored separately. For meal prep, assemble everything except the celery topping, bake, then add the topping fresh before serving. Garnish with parsley and lemon zest right before eating for maximum brightness.
Why You’ll Love This Recipe
- One-Pan Magic: I swear by this recipe when I’m too tired to wash extra dishes—just toss the tuna, mushrooms, and shallots on a sheet pan, drizzle with olive oil, and let the oven do the work. The celery and garlic soften into a fragrant, caramelized blanket around the tuna, so you end up with a dish that’s almost gourmet but requires zero cleanup.
- Umami Bomb: Between us, that combo of white mushrooms and shallots is where this dish gets its superpower. The mushrooms soak up the garlic like a sponge, then crisp at the edges while the tuna stays tender—it’s the kind of flavor that makes you pause mid-bite, like, “Wait, is this actually this good?” (Yes. It is.)
- Weeknight Flex: This recipe is my go-to when I’m feeding a crowd but don’t want to slave over the stove. Bake it once, serve it twice: slice the leftovers into a hearty salad the next day or toss them into a grain bowl. Honestly, the tuna holds up better than you’d think—no sad, dry fish here.
- Budget Protein Win: Fresh tuna steak can feel fancy, but this method stretches it into something ridiculously affordable. The mushrooms and celery bulk it up, so you’re basically getting two servings’ worth of veggies for the price of one. Plus, it’s cheaper than takeout but way more impressive when you bring it to potlucks. (My secret weapon.)
Step-by-step instructions for baked tuna with celery topping
Here’s the method for achieving that perfect balance of crispy exterior and creamy interior.
Prepare the Tuna and Celery Topping
Preheat your oven to 425°F. Pat the 1.5 lb fresh tuna steak dry with paper towels—this ensures maximum crispiness. Place the tuna in a baking dish and brush both sides generously with 2 tablespoons extra-virgin olive oil. Season immediately with 1.5 teaspoons salt and 0.5 teaspoon black pepper, pressing the seasoning into the flesh.
In a small bowl, combine the 3 whole celery stalks (thinly sliced), 0.5 cup panko breadcrumbs, 1 teaspoon lemon zest, and 0.25 cup fresh parsley. Mix well to distribute the breadcrumbs evenly. This topping will create that signature crispy crust we’re after.
Create the Mushroom Filling
Heat 1 tablespoon extra-virgin olive oil in a skillet over medium heat. Add the 8 oz white mushrooms (sliced thin) and cook for 5-6 minutes until they release their moisture and begin to brown. Remove the mushrooms and set aside.
In the same skillet, add the 2 whole shallots (minced) and 3 cloves garlic cloves (minced). Cook for 2-3 minutes until softened and fragrant. Deglaze the pan with 2 tablespoons dry sherry, scraping up any browned bits from the bottom. Stir in the 1 tablespoon Dijon mustard and 0.5 cup heavy cream, then return the mushrooms to the skillet. Simmer for 3-4 minutes until the sauce thickens slightly. Remove from heat and let cool for 5 minutes before spooning it over the tuna.
Assemble and Bake to Perfection
Spread the mushroom mixture evenly over the tuna steak, pressing down gently to ensure even contact with the fish. This layer will infuse the tuna with rich, savory flavors while keeping it moist. Sprinkle the celery topping mixture evenly over the mushroom layer, pressing down lightly to help it adhere.
Bake for 12-15 minutes until the celery topping is deep golden brown and crispy, and the tuna reaches an internal temperature of 125°F (for medium-rare). The center should still be slightly pink—overcooking will make the tuna dry. If the topping browns too quickly, tent loosely with foil for the last 5 minutes of baking.
Rest and Serve
Remove the tuna from the oven and let it rest for 5-7 minutes before serving. This resting period allows the juices to redistribute, ensuring each bite is moist and flavorful. The crispy celery topping will soften slightly but maintain its texture, while the creamy mushroom filling will stay rich and cohesive.
Slice the tuna into 4 equal portions and serve immediately, garnished with additional fresh parsley if desired. The contrast of the crispy topping, creamy filling, and tender tuna creates a truly memorable dish. Pair with a simple green salad or steamed vegetables to complete the meal.
Pro Tips For Making Baked Tuna
- USE HIGH HEAT FIRST: Sear the tuna steak in a screaming-hot pan for 30 seconds per side before baking—it locks in juices and builds flavor faster than slow baking alone. I used to skip this, and my tuna always ended up dry and bland.
- SLICE SHALLOTS THINLY: Shallots should be paper-thin—almost translucent—so they soften without disappearing into mush. Thick slices turn to mush while tuna cooks, and nobody wants a mushy side dish.
- DON’T OVERBAKE THE TUNA: Tuna’s done when it hits 120°F (49°C) internally—any hotter, and it turns rubbery. Use an instant-read thermometer, or cut into the thickest part: it should flake easily but still hold shape.
- SAUTE MUSHROOMS FIRST: Cook mushrooms until they release their moisture and brown slightly before adding them to the baking dish. This prevents a soggy bottom and deepens their earthy flavor—trust me, it makes a real difference.
Troubleshooting this recipe
Celery Topping Too Soft
If your celery topping isn’t crispy enough, the issue is usually undercooked breadcrumbs or excess moisture. First, ensure you’re using Japanese panko—it’s lighter and crisps better than regular breadcrumbs.
For extra insurance, toast the panko in a dry skillet over medium heat for 2-3 minutes before mixing with celery. Also, pat the tuna completely dry before baking, as any moisture will steam the topping instead of crisping it. 🔥
Mushroom Filling Too Watery
A watery mushroom filling often means the mushrooms weren’t cooked long enough to release their moisture. Sauté them for at least 8 minutes until they’re deeply browned and most of the liquid has evaporated.
If your filling still looks thin after simmering with cream, stir in 1 teaspoon cornstarch mixed with 1 tablespoon cold water and cook for 1 more minute until thickened. Avoid overcrowding the pan—cook mushrooms in batches if needed. 💫
Tuna Overcooked or Dry
Tuna dries out quickly when baked, so never exceed 125°F internal temperature for medium-rare. Use a meat thermometer inserted horizontally into the thickest part to monitor.
If your tuna is overcooked, try this fix: After baking, place the dish in a 350°F oven for 5-10 minutes with a damp paper towel over the tuna to restore moisture. For next time, reduce oven temp to 400°F and bake for 10-12 minutes instead of 15. ⏰
Topping Falling Off
The celery topping often slides off because it lacks adhesion. Before baking, press the topping down firmly with the back of a spoon, and consider adding 1 tablespoon Dijon mustard mixed into the mushroom filling—it acts as a glue.
Another trick? Lightly brush the tuna with 1 tablespoon beaten egg white before adding the topping. For extra grip, sprinkle 1 teaspoon grated Parmesan into the celery mixture. 💪
Frozen Tuna Issues
If using frozen tuna, thaw it in the fridge overnight—never in cold water, as it can make the meat mushy. Once thawed, **pat it very dry with paper towels and let it sit at room temperature for 10 minutes before seasoning.
Frozen tuna releases more moisture, so reduce the mushroom filling slightly (use 0.4 cup heavy cream instead of 0.5) to prevent a soggy texture. 🧊
Sauce Separating After Baking
If the mushroom filling separates after baking, the heavy cream was likely too hot when mixed. Always cool the sauce to room temperature before spreading it over the tuna. For extra stability, whisk in 1 teaspoon cold butter** at the end to emulsify the sauce.
If separation still happens, reheat the sauce gently on the stovetop, stirring constantly until smooth, then cool before using. 🥄
Nutrition facts
Frequently asked questions
Can I substitute fresh tuna with canned tuna in this recipe?
Fresh tuna is ideal for this baked recipe because it delivers the best texture and flavor. Canned tuna is too dense and dry for baking, and it won’t achieve that perfect medium-rare center. If you must use canned, try a high-quality, oil-packed variety and serve it as a side dish instead of the main baked component.
How do I know when the tuna is fully cooked?
Use a meat thermometer to check the internal temperature—125°F for medium-rare is perfect. The center should still be slightly pink, not gray. For extra confidence, bake for 12 minutes at 425°F and check the temperature before removing from the oven. Overcooking will make the tuna dry and tough.
Can I make this recipe ahead of time?
Yes! Prepare the mushroom filling and celery topping separately up to 1 day ahead. Store them in airtight containers in the fridge. Assemble the dish just before baking—this keeps the celery topping crispy. The baked tuna holds well for 2 hours at room temperature, but the topping will soften slightly. For best results, bake fresh and serve immediately.
What’s the best way to reheat leftovers?
Reheat gently to preserve texture: wrap leftovers in foil and warm at 350°F for 5-7 minutes, or use the microwave for 20-30 seconds**. The celery topping won’t regain full crispiness, so consider adding fresh topping when reheating. For extra moisture, drizzle with a little heavy cream before reheating.
What wine pairs best with this dish?
A crisp Sauvignon Blanc or light Pinot Noir complements the dish beautifully. The acidity of Sauvignon Blanc cuts through the richness of the mushroom filling, while Pinot Noir’s earthy notes enhance the umami. For a non-alcoholic option, try sparkling water with lemon or a dry sparkling wine.
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