Scallops: Place vermouth, garlic, tarragon and sea scallops in a large resealable plastic bag. Refrigerate for 2 hours or up to 6.

Cream Sauce: In a medium-size saute pan, heat olive oil over medium heat. Add onion and cook 5 minutes or until onion is tender. Add garlic and pepper and cook 1 to 2 minutes; add vermouth and cook over high heat 3 minutes. Add half and half and cook over high heat 3 to 4 minutes or until slightly thickened. Stir in tarragon and Parmesan; remove from heat and let cool. Cover surface with plastic wrap and refrigerate until ready to serve.

To serve, heat broiler. Reheat sauce over very low heat. Pat scallops dry. Cover broiler pan with nonstick aluminum foil. Place scallops on foil; sprinkle with salt and pepper. Place under broiler, 4 inches from heat. Broil 5 to 6 minutes or until golden brown. Divide warmed sauce among 8 plates. Place 2 scallops on sauce on each plate.