In a large straight sided frying pan melt butter over medium-high heat. Add shallots and saute until soft, about 2 minutes.
Add Champagne, parsley and lemon juice to pan. Bring to a boil then reduce heat to a simmer.
Slide chicken into Champagne mixture and poach 15 minutes, turning once. (Use an instant-read thermometer to be sure the internal temperature is 165 degrees F.) Remove chicken with a slotted spoon to a plate; set aside.
Ladle 1/2 cup of poaching liquid into a small pot over medium heat. Add cream and bring to just under a boil. Reduce heat and simmer. Whisk in white sauce mix. Simmer 1 minute, stirring constantly.
To serve chicken, spoon sauce over top and garnish with parsley and grape salad.
Combine all ingredients in medium bowl; mix well. Season, to taste, with salt and pepper Use as garnish for poached chicken.