Blend Roasted Garlic Mustard, cream, clam broth, parsley and capers together in a small bowl. Set aside.
Place seasoned flour in a flat dish and coat snapper fillets on both sides.
Heat oil in a large, heavy skillet over medium-high heat. Add fillets flesh side down and sauté over medium heat until lightly browned, about 3 minutes.
Turn fish with a long metal spatula, and sauté second side for 3 minutes. Transfer to a heated platter or plates while finishing sauce.
Wipe out skillet if there are burned bits. Pour in mustard cream mixture, bring to a boil and allow to reduce briefly. Spoon over fish and serve.