Green Beans & Mushrooms

2 cans Green Beans (or 2 pkgs Frozen French Style Green Beans)
1 6oz can Mushrooms, sliced
1 5oz can Water Chestnuts, drained and chopped (optional)
1 Tbls Milk
1/4 tsp Salt
dash of Pepper
2 Tbls Flour
2 Tbls Onion, chopped
1 cup Sour Cream
1 8oz pkg Swiss Cheese, grated
Corn Flakes, crushed

Preheat oven to 400F. Lightly grease casserole dish. Cook green beans as directed. Drain well. Combine butter, flour, salt,pepper, onions, mushrooms, water chestnuts (if used), and sour cream. Mix lightly with green beans. Place mixture in casserole dish. Top with grated cheese; sprinkle with corn flakes. Bake for 20 minutes or until bubbly. Serves 8.