Hazelnut-crusted trout with brown butter and fennel salad
Ingredients
- 1¾ lbs 800 g trout or salmon, boneless fillettrout or salmon, boneless fillets or white fish filletwhite fish fillets
- ½ tsp ½ tsp salt
- ¼ tsp ¼ tsp ground black pepper
- 1 1 egg white largeegg whites large
- ½ cup (21⁄3 oz.) 120 ml (70 g) hazelnuts finely chopped
- 1 tbsp 1 tbsp olive oil
- 4 tbsp 4 tbsp butter
- 1 tbsp 1 tbsp lemon juice fresh
- salt if needed
- 1 lb 450 g fresh fennel trimmed
- 2 tbsp 2 tbsp olive oil
- 2 tbsp 2 tbsp lemon juice fresh
- 2 tbsp 2 tbsp fresh parsley chopped
- salt to taste
- ground black pepper, to taste
- Net carbs 7g 4%
- Protein 45g 25%
- Fat 59g 72%
Fiber 5g
Total Carbs 12g
Instructions
- Thinly slice the fennel, preferably using a mandoline. Toss with olive oil, lemon juice, parsley, salt, and pepper. Set aside while preparing the trout.
- Place the chopped hazelnuts in a shallow bowl. In a separate bowl, whisk the egg white until frothy.
- Pat the trout fillets dry with paper towels and season with salt and pepper. Brush the flesh side with egg white, then press the hazelnuts onto the surface to form an even crust. Lightly drizzle with olive oil.
- Preheat the air fryer to 350°F (175°C). Arrange the trout fillets in a single layer in the air fryer basket, hazelnut side up. Air-fry for 7–10 minutes, depending on thickness, until the crust is golden and crispy and the fish flakes easily. The internal temperature should reach 145°F (63°C). Avoid turning the fillets to keep the crust intact. Cook in batches if necessary.
- Meanwhile, melt the butter in a small saucepan over medium heat. Swirl the pan occasionally as the butter foams. Continue cooking until the milk solids turn golden brown and the butter develops a nutty aroma. Remove from the heat immediately, carefully stir in the lemon juice, and season with salt if needed.
- Divide the fennel salad among serving plates and add the trout. Spoon the warm lemon brown butter over the fish just before serving.
Recipe notes and tips
How do I get the perfect hazelnut crust?
Finely chop the hazelnuts with a knife or pulse briefly in a food processor until coarsely ground, but not powdered. Pat the fish thoroughly dry before brushing it with egg white, then gently press the nuts onto the surface.
Preheat the air fryer and arrange the fillets in a single layer without overcrowding the basket. Good air circulation helps the hazelnuts toast evenly and develop a crispy crust. Avoid turning the fish during cooking to keep the coating intact.
Can I use another fish?
Absolutely! Salmon, Arctic char, or steelhead trout are excellent alternatives. You can also use cod or halibut, although cooking times may vary depending on the thickness of the fillets. Choose fillets that are thick enough to hold together during cooking.
What can I use instead of fennel?
If you're not a fan of fennel, try thinly sliced green cabbage, cucumber, or zucchini instead. Green cabbage adds a satisfying crunch, cucumber gives the salad a refreshing twist, and raw zucchini has a mild flavor that pairs beautifully with the lemon dressing. Use the same amount and prepare the salad as directed.
Can I make this in the oven?
Yes! Preheat the oven to 400°F (200°C). Arrange the prepared trout on a parchment-lined baking sheet, hazelnut side up. Bake for approximately 12–15 minutes, depending on thickness, until the crust is golden and the fish reaches an internal temperature of 145°F (63°C).
What's the secret to perfect brown butter?
Use a light-colored saucepan so you can easily see the butter changing color. Swirl the pan frequently and watch closely once the butter starts to foam. As soon as the milk solids turn golden brown and smell nutty, remove the pan from the heat to prevent burning.
Can I prepare the fennel salad ahead?
Yes! You can slice the fennel a few hours ahead and store it in an airtight container in the refrigerator. For the freshest flavor and crunch, toss it with the dressing shortly before serving.
Storage and leftovers
Store leftover trout and fennel salad separately in airtight containers in the refrigerator for up to 2 days. Reheat the fish gently in the oven or air fryer to help preserve the hazelnut crust. The fennel salad is best enjoyed fresh.

























