In a skillet over medium high heat, in hot salad oil, cook turkey legs until well browned on all sides. Add water, onion, salt, and pepper. Heat until boiling. reduce heat to low and cover and simmer for 1 1/2 hours or until turkey is fork tender.
Remove turkey from skillet and cool slightly until easy to handle. Cut turkey meat into one inch pieces. Discard skin and bones.
Meanwhile over high heat cook turkey broth in skillet until it reduces to about one and a half cups. In a small bowl with spoon, blend flour with 1/2 cup half-and-half, Gradually stir in remaining half-and-half.
Cook stirring until cream sauce boils and is thickened.
In another skillet over medium heat stir in butter and cook mushrooms until tender and gently stir into cream sauce with turkey meat and champagne and 1/4 cup parsley.
Heat carefully until hot.
To serve, spoon turkey mixture into dish if you like. Garnish with remaining parsley, serve with white rice or even mashed potatoes.