1⁄2 cup extra-virgin olive oil, plus 4 tbsp.
2 large yellow onions
4 medium tomatoes
16 cloves garlic, smashed
10 sprigs each of fresh thyme and oregano,
plus 1⁄2 tbsp. each of fresh thyme
and fresh oregano, roughly chopped
Kosher salt and freshly ground black pepper
4 10-oz. salmon steaks
4 thin slices of lemon
2 tbsp. fresh tarragon
2 tbsp. Pernod
1. Heat oven to 450°. Line a baking sheet with aluminum foil and grease it with 1⁄4 cup of the olive oil. Cut onions into 1⁄4"-thick rings; cut tomatoes into 1⁄2" slices. Spread the onions and the tomatoes out on the baking sheet to form a bed for the salmon steaks. Tuck garlic and sprigs of fresh thyme and oregano between vegetables and drizzle with another 1⁄4 cup of the oil. Season the vegetables with salt and pepper to taste. Roast the vegetables until soft and juicy, about 25 minutes.
2. Remove the baking sheet from the oven. Arrange an oven rack 3" from the broiler element; turn oven to broil and heat. Arrange salmon on top of the roasted vegetables, drizzle with 2 tbsp. of the oil, and season with salt and pepper to taste. Place 1 slice of lemon on each salmon steak and sprinkle chopped thyme and oregano over the fish. Broil the salmon until lightly browned and just cooked through, about 5 minutes.
3. Sprinkle the salmon steaks with tarragon, Pernod, and remaining 2 tbsp. of oil.