Tuna Tartare Avocado Mousseline
By Emma
Certified Culinary Professional
•
Recipe tested & approved
Raw tuna diced finely mingles with scallions, toasted sesame, and a soy-lime dressing. Creamy avocado whipped with lime and a hint of horseradish heat forms a mousseline to mellow sharpness. Served on crisped baguette slices with a peppery micro green finish. Balances texture: silky fish, lush avocado, crunchy croûtons. Simple, fast, fresh. No dairy or nuts. A sharp zesty bite from lime zest, warmth from toasted sesame oil, subtle wasabi punch. Bright colors, fresh ocean aroma, and crunch contrast make this a light, clean starter or snack.
Prep:
20 min
Cook:
5 min
Total:
25 min
Servings:
4 servings
#fusion cuisine
#seafood
#raw fish
#appetizer
#quick prep
#fresh herbs
#sashimi-grade tuna
Raw tuna. That gentle ocean aroma hitting you, fresh fish barely touched. I used to blow it by overmixing or dulling the sharpness — learned to keep it simple. Added preserved ginger one night on a whim; nailed the sweet-spicy balance. Avocado needs to be creamy, but too smooth turns boring. Whipping with horseradish instead of straight wasabi keeps it interesting, a bit earthy and less aggressive. Lime juice isn’t just sour, it brightens and stops avocado browning if you move fast. Toasted sesame oil’s fragrance pops if you lightly warm it a second, never use cold oil. Croûtons must be dry, or they flop and ruin the mouthfeel. You’ll hear that crunch; that snap is as important as the tartare taste. Trust your senses — the aroma of lime zest, the silky avocado texture, the tender firmness of tuna. It’s a dish that’s quick but demands precision.
Ingredients
Mousseline
- 1 ripe Hass avocado
- 20 ml lime juice
- 3 ml grated fresh horseradish
- pinch of salt
Tartare
- 2 scallions finely chopped
- 20 ml tamari soy sauce
- 10 ml toasted sesame oil
- 450 g sashimi grade tuna finely diced
- 15 ml toasted black and white sesame seeds
- 1 lime zest grated finely
- 30 g baby arugula
- 4 baguette croûtons grilled
- extra virgin olive oil drizzle
Twist additions
- 5 ml yuzu juice
- 5 g finely diced preserved ginger
About the ingredients
Avocado quality makes or breaks the mousseline. Always choose ripe but firm, not overripe mushy fat bombs. Lime juice is the best acid here, fresh squeeze only. Fresh horseradish replaces wasabi because it offers earthier heat and blends with yuzu instead of just a hit of spice. Use sashimi-grade tuna — no compromises, or go for Arctic char or yellowfin if tough. Scallions provide subtle onion note with soft bite. Tamari soy works better than regular soy sauce here — less salt, more depth. Toast sesame seeds yourself to unlock oils and aromas; store sealed to avoid rancidity. Baby arugula adds pepper, but micro cilantro, shiso, or even finely sliced cucumber ribbons work well too, depending on mood. Croûtons made from day-old baguette grilled dry deliver crunch; avoid oily toasts that sog and weigh down. Olive oil drizzle at the end elevates all elements but don’t overdo — too much oil flattens flavors. Yuzu juice and preserved ginger are my twist — yuzu for a citrus floral lift, preserved ginger for sweet-spicy layers. Don’t skip them unless unavailable — they keep this tartare lively.
Method
Mousseline preparation
- Cut avocado flesh into chunks, toss immediately with lime juice to prevent browning. Pulse briefly in food processor with freshly grated horseradish until creamy but still slightly textured — not a puree. Salt lightly to balance earthiness. Cover tightly with plastic wrap pressed to surface; chill while prepping tartare. The slight coarse texture adds more bite than smooth avocado cream, allowing it to sit better next to fish.
Tartare assembly
- Combine scallions, tamari, toasted sesame oil, yuzu juice, and diced preserved ginger in a bowl. Stir to marry flavors - this will season the tuna. Gently fold in diced tuna; careful not to mash. Taste test now and adjust salt or acidity. The preserved ginger adds an unexpected sweet-spicy pop, cutting raw fish richness and complementing toasted sesame’s nuttiness. Let sit 5 minutes to amalgamate but no longer or tuna loses freshness.
Plating
- Chill four plates beforehand; cold slows avocado and fish from softening too quickly. Use a ring mold or any circular cutter to shape tartare: pack tuna first, gently pressing down but not compacting. Layer a quenelle of avocado mousseline close by or on top for contrast. Sprinkle sesame seeds over both elements, zest lime finely atop to release oils and fragrance. Garnish with baby arugula — peppery and crisp, works like a palate refresher here.
- Arrange warm grilled baguette croûtons on side; they must be dry crisp, not greasy, to add crunch. Finish with a light swirl of quality extra virgin olive oil. This oil adds fruity brightness and smooth mouthfeel, contrasting with toasted sesame’s deep aroma.
- Serve promptly to avoid avocado discoloration or fish warming up. Tuna must be very fresh; if unavailable, substitute with fresh yellowfin or Arctic char for a similar texture but softer flavor profile. Wasabi replaced here by fresh horseradish because it blends better with green avocado and yuzu acidity, less one-note heat but a complex rhizome sharpness.
Troubleshooting and tips
- If avocado begins oxidizing before serving, cover tightly and add a tear or two of extra lime juice to refresh color. If tuna juice pools, drain slightly on paper towel before mixing - keeps tartare clean. For an alternative base, substitute baby arugula with micro cilantro or shiso leaf for different herbal notes. Baguette stale? Use rice crackers or toasted lavash instead; texture contrast critical.
- Timing is key. Don’t prep tartare and leave it too long — fish loses texture, flavors dull. Avocado mousseline can be prepped hours ahead but keep chilled and sealed.
- The goal: balance savory, acidity, creaminess, and texture. Each element matters; skipping one leads to a flat plate. Sesame oil must be toasted – raw sesame oil is bitter here. And always, trust your nose and palate — no recipe fixes bad quality ingredients.
Cooking tips
Start with mousse preparation. Mixing avocado with lime ASAP stops browning, but keep it slightly textured — you want cream, not goo. The horseradish isn’t just heat; freshly grated, it delivers an aroma some miss with powdered wasabi. Chill covered to keep that color. For the tartare, mix liquids, then toss in tuna carefully — no smushing, just fold. Letting the mixture rest 5 minutes melds flavors but don’t push longer or fish goes watery. Shape with a ring mold on chilled plates — the cold stops avocado from melting and keeps fish firm. Garnishes aren’t decoration — sesame seeds bring crunch and nuttiness; lime zest scents bright acidity; baby arugula cuts richness with peppery bite. Serve immediately with crisp croûtons, or the contrast collapses. If tuna juice is too wet, blot before mixing; you want flavor, not soup. Recipe may look quick but requires timing finesse and fresh ingredients. Overdo the dressing, and the fish can lose texture; undersalt, dull flavors. Adjust salt and acid as you go — taste, trust instincts. Oil drizzle last step, sparingly, for a glossy finish and counterpoint to tartare’s punch. Don’t rush plating. A good tartare is about patience and respect for raw fish textures and avocado freshness.
Chef's notes
- 💡 Keep avocado chunks noticeable, not a puree. Overprocessing lets it turn gluey. Pulse briefly after tossing with lime juice — stops browning, keeps texture intact. Horseradish grated fresh adds earthy heat, not just sharp spice. Chill tightly covered or mousse oxidizes faster. Remember, a slightly coarse mousseline sits better with fish; texture contrast matter.
- 💡 Marry tartare flavors by stirring liquids first: tamari, sesame oil, yuzu, diced ginger. Fold tuna in gently — smashing kills texture and mouthfeel. Let sit 5 minutes maximum for flavors to meld. Longer resting dulls freshness, juices separate and create sogginess. Taste test for salt, acidity often — ginger adds punch so be cautious not to overdo lime or salt.
- 💡 Use cold plates when plating; chilled surface delays softening. Press tuna into ring mold gently, no compacting. Close-by avocado quenelle adds creamy relief. Sprinkle toasted sesame seeds just before serving — their fragrance pops once placed, not earlier. Lime zest top releases aroma and oils; do not skip. Baby arugula pepper adds necessary bite cleaning palate between mouthfuls.
- 💡 Bread croûtons dry and crisp, avoid oily or soggy slices — ruin crunch interplay critical here. Warm grilled day-old baguette preferred, heat triggers toasty smell. Drizzle olive oil sparingly at end for a glossy finish and fruity depth. Toasted sesame oil must be gently warmed; cold oil smells bitter and heavy. Use freshly toasted sesame seeds for best aroma; store sealed tightly to avoid rancidity.
- 💡 If avocado oxidizes early, tightly cover and add more lime juice — acid refreshes color fast. Tuna juice pooling? Drain on paper towel before mixing to keep tartare texture clean, not soupy. Substitute tuna with fresh yellowfin or Arctic char when unavailable. Baby arugula replaceable with micro cilantro or shiso leaf — alters herbal lift. For croûtons alternative: rice crackers or toasted lavash keeps crunch without heaviness.
Common questions
How to keep avocado from browning?
Toss with lime juice immediately. Chill fast and cover tightly. Add more lime just before serving if you spot oxidation. No air means slower browning. Fresh lime juice acidity critical. Don’t over-process mousse; some texture helps slow oxidation.
Can I use other fish besides tuna?
Yes, yellowfin and Arctic char work well. Similar firm texture but differ flavor profile. Avoid oily or soft fish or tartare becomes mushy. Frozen sashimi-grade also option but drain excess moisture well. Tuna gives distinctive taste, but alternatives extend availability.
What if tartare gets watery?
Drain tuna on paper towels before mixing. Excess liquid dilutes dressing, makes mushy. Also, avoid overmixing or breaking fish chunks. Resting too long leads to juice separation. Mix just before serving for freshest texture and avoid sogginess.
Best way to store leftovers?
Wrap mousse and tartare separately with plastic wrap pressed on surface. Keep chilled. Mousse oxidizes quickly; tartare loses texture and freshness if stored long. Up to 24 hours max but expect some flavor dulling. Reassemble fresh just before serving if possible.
