DO-AHEAD TIP: Marinate snapper fillets for 30 minutes (see recipe).
Preheat oven to 375 degrees.
In a small bowl, combine first 6 ingredients (mustard through black pepper); blend well then rub mixture over the top of each fillet; cover and refrigerate for 30 minutes.
Place snapper fillets, plain sides down, in a lightly oiled 9- x 13-inch baking dish. Bake for 20 to 25 minutes or until fish flakes easily when tested with a fork.