Preheat the oven to 450°F. 

Line a large baking sheet with foil and lightly oil the foil.

Place salmon skin-side down on the foil. 

Run your fingers over the flesh to feel for pin bones; use tweezers or needle nose pliers to pull out any bones. 

Sprinkle salmon with 1/2 teaspoon of the salt.

In a food processor, combine parsley, horseradish, shallots, oil, mustard, lemon zest, lemon juice and remaining 1/2 teaspoon salt. 

Pulse until the mixture is very finely ground. 

Spread mixture evenly over top of salmon, pressing it down to help it adhere. 

Bake salmon in top third of the oven until cooked through and crust begins to brown, about 20 minutes.