Preheat oven to 350F.
In a large bowl, combine sour cream, milk, water, salt, and pepper mixing until incorporated.
Stir in the item from Group A
Stir in one item from each of Groups B, C, D, and E (again, no sour cream and milk when using tomatoes)
Spoon mixture into a lightly greased 13- x 9- x 2-inch baking dish.
Sprinkle with one or two choices from Group F.
Cover and bake the casserole at 350 F, for 1 hour and 10 minutes. Uncover and bake 10 additional minutes. Servings: About 6.