Creme Fraiche: 2 Cups Whipping Cream and 1 Tablespoon Buttermilk. Mix together in covered jar and shake 2 minutes. Let stand at room temperature 8 hours, or until thick. Place in refrigerator.
Melt 2 Tablespoons Butter in a 1-quart saucepan over medium heat and sauté carrots 5 minutes. Reduce heat, add celery and cook 5 minutes.
Add cucumber and mushrooms, cover and cook an additional 5 minutes. Add more butter as necessary during cooking.
Meanwhile, In separate pan, reduce wine by one-half.
In a large skillet, melt remaining 2 Tablespoons Butter over medium heat and sauté scallops 30 seconds or until opaque; do not allow to brown.
Deglaze vegetable pan with reduced wine. Add vegetables with their pan juices and Creme Fraiche. Cook 3 minutes and season to taste with salt and pepper.
Scallops should not be overcooked. Remove scallops and vegetables from pan and reduce sauce to desired thickness over medium-high heat.
If more sauce is desired, add a bit more heavy cream and butter an continue to reduce. Return scallops and vegetables to sauce and serve. Garnish with chervil and/or parsley.