Poppyseed Chicken Casserole

1/2 cup butter
1 up crushed ritz crackers
1 tablespoon poppy seeds
4 chicken breasts (cooked and cubed)
1 can cream of chicken soup
1 1/2 cup sour cream

Topping:
1/2 cup crushed ritz crackers
3 tablespoons parmesan cheese

Melt butter, add crackers and poppyseeds.  Stir in remaining ingredients.  Pour into 9x13 pan.  Top with ritz cracker topping.  Bake for 20 minutes at 350.