-This recipe can be made ahead in a few simple steps:1. Cook the potatoes, up to two days ahead, let cool, peel and grate into pan. Cover with plastic wrap by pressing closely to the potatoes to avoid browning. Store in refrigerator.2. Cook the chicken, chop and set in refrigerator until ready to use, up to four days ahead. 3. Chop the vegetables, place in a ziplock bag in refrigerator or saute in butter, cool and place in refrigerator until ready to make sauce. Or finish cooking the vegetables and making the sauce until ready to assemble casserole. -If you assemble the casserole ahead of time and don't bake immediately, reduce the amount of potatoes a bit ( I use about 6 cups of potatoes instead of 7-8 for make ahead). The potatoes absorb the sauce and the casserole dries out a bit to much if using 8 cups of potatoes. If you are making the casserole and baking immediately, 7-8 cups of potatoes works well. -If you would like to use cream of chicken soup instead of making your own sauce, reduce the butter to 2 tablespoons (for sautéing vegetables) and omit the flour and salt. Use 1 can soup, 1 cup milk, one can or about 14-16 oz chicken broth and salt to taste. Everything else stays the same. You may also use a 12 oz bag of frozen hash browns in place of the cooked and grated potatoes. The hash browns should be thawed before using. -This recipe works well in 2- 8x8 disposable pans. I make this ahead and take to friends or neighbors in need. Each pan serves about 4 adults.