This one is in every church cookbook that I own.
2-3 chicken breasts, cooked and diced
1 can cream of chicken soup (I make my own)
8 oz. sour cream
1 stick butter or margarine (I use butter)
1 sleeve Ritz crackers (I used reduced fat) - crushed
1- 1 1/2 teaspoons poppy seeds
In large bowl, stir together the chicken, soup and sour cream. Spread into casserole dish. Melt butter and mix with cracker crumbs and poppy seeds. Sprinkle over chicken mixture. Bake at 350 degrees for about 30 minutes.