Prep: 1. Preheat oven to 350. 2. Spread hazelnuts in a single layer on a rimmed baking sheet and toast, stirring occasionally, until golden, 8-10 minutes. Coarsely chop; set aside. 3. Reduce oven temperature to 300. Make: 1. Scatter tarragon sprigs on a large rimmed baking sheet. Place halibut on top, drizzle with 2 tablespoons oil, and season with salt and pepper. 2. Roast until halibut is just opaque in the center, 20-30 minutes, depending on thickness of fish. 3. Meanwhile, melt butter in a saucepan over medium-high heat. Cook, stirring often, until butter foams, then browns (don't let it burn), ~5 minutes. 4. Remove from heat; let brown butter cool slightly. Stir in 1/4 cup fresh squeezed lemon juice, hazelnuts, and remaining 2 tablespoons oil; season with salt and pepper. 5. Serve fish with hazelnut brown butter sauce and lemon wedges.
Halibut can sometimes be a little pricy. Try this recipe with cod, which is equally as delicious! Check out our tips for buying and cooking fish here - http://blog.gatheredtable.com/2015/06/21/a-beginners-guide-to-how-to-buy-and-cook-fish/ Looking for a good substitute? Many fish types are extremely versatile, check out our recommended substitutions here - http://blog.gatheredtable.com/2015/06/21/recipe-hacking-how-to-substitute-different-types-of-fish/