In a large bowl or a rimmed baking sheet, stir the 4 cups of water and 4 tablespoons of salt until the salt is mostly dissolved. Submerge the salmon fillet in the water for 10 minutes. This prevents the "white stuff" (albumin) from leaking out during baking.
4 cups cold water, 4 tablespoons salt, 2 to 3 pound whole salmon fillet
While the fish soaks, preheat the oven to 400°F, and line a large baking sheet with parchment paper.
Remove the salmon from the brine. Use paper towels to pat the fillet completely dry on both sides. Place the fish skin-side down on the prepared pan.
In a small bowl, whisk together the olive oil, minced garlic, Italian seasoning, salt, pepper, and the juice from half of the lemon.
2 tablespoons olive oil, 3 garlic cloves, 1 ½ teaspoons Italian seasoning, ¼ teaspoon salt, ¼ teaspoon black pepper, ½ large lemon
Spread the mixture evenly over the top of the salmon, covering it from edge to edge. Lay the lemon slices across the top of the fish.
½ large lemon
Place the pan into the center rack of the oven, and bake. Start checking at 12 minutes for thin fillets (1 inch) and at 18 minutes for thick fillets (1.5 inches).
Check with a meat thermometer in the thickest part of the fish. Remove the salmon from the oven the moment it hits 130°F.
Let the salmon rest on the pan for 5 minutes. The temperature will naturally rise to 135°F. Garnish with fresh herbs and serve immediately.
1 tablespoon fresh parsley or dill