Melt 1 teaspoon butter in a large non-stick skillet over medium heat. Add scallops, shallots and tarragon and saute until scallops are translucent, 3 minutes. Remove with a slotted spoon to a medium-size bowl.
Add milk, wine, and mustard to skillet. Bring to boiling. Stir together cornstarch and water in a small cup; stir into skillet. Cook, stirring, until thickened. Remove from heat. Stir in Jarlsberg until melted. Add to scallops.
Mix together bread crumbs, Parmesan cresses, remaining 2 teaspoons butter, salt and pepper in a small bowl. Spoon scallop mixture into six 1/2-cup oven-proof ramekins or scallops shells. Top with bread crumb mixture. Bake in heated 400 degree F. oven 10-13 minutes or until cheese is bubbly and crumbs are golden. Serve with lemon wedges.