Slow-Roasted Salmon with Tarragon and Citrus

Ingredients

1. 4 tablespoons unsalted butter, melted
2. 4 garlic cloves, very thinly sliced
3. 3 medium shallots, minced
4. 2 tablespoons fennel seeds, coarsely ground in a spice grinder
5. Finely grated zest of 3 lemons, plus 1 1/2 tablespoons fresh lemon juice
6. Finely grated zest and juice of 1 orange
7. 2 tablespoons chopped tarragon
8. 1 tablespoon coarsely ground black pepper
9. 2 teaspoons chopped thyme
10. Extra-virgin olive oil, for the baking dish
11. One 2 1/2-pound whole fillet of skinned salmon
12. Kosher salt
13. 1/2 teaspoon cayenne pepper
14. Flaky sea salt, for sprinkling

1. In a bowl, combine the melted butter with the garlic, shallots, ground fennel seeds, lemon zest, orange zest, tarragon, black pepper and thyme.
2. Preheat the oven to 300°. Brush a large glass or ceramic baking dish with olive oil. Lightly season the salmon fillet with kosher salt. Spread half of the seasoning mixture on the skinned side of the fish. Place the salmon skinned side down in the baking dish and fold the thin tail end under itself to make the fillet an even thickness. Stir the cayenne pepper into the remaining seasoning mixture and spread it over the salmon. Let the salmon stand at room temperature for 20 minutes.
3. Carefully pour the orange juice into the baking dish and cover the baking dish tightly with aluminum foil. Bake the salmon for about 35 minutes, until it is barely opaque in the center.
4. Sprinkle the salmon with the lemon juice and sea salt and serve.