Poppy Seed Chicken

3 cups cooked, cubed chicken
1 ½ cans cream of mushroom soup
1 cup sour cream
1 ½ sleeves Ritz crackers, crushed
1 cube butter
1 ½ tbsp. poppy seeds

*Place chicken in bottom of greased aluminum 9x13 pan. Smaller if dividing. Mix sour and sour cream. Pour over chicken. Melt butter and stir into crushed crackers. Add poppy seeds and mix together. Spread cracker mixture over chicken. Cover with foil and freeze. When ready to eat, thaw and bake at 375 for 30 minutes.