Cheesy Shrimp Casserole

1 4 oz can mushrooms drained
2 tbsp butter
2 6 1/2 cans or 1 lb cooked shrimp
2 cups cooked rice
1 cup shredded cheddar cheese
1/2 cup evaporated milk
2 tbsp ketchup
1 tbsp Worcestershire sauce
dash of pepper

Preheat oven to 350º

Slice mushrooms and cook slowly in butter until tender. Mix lightly
with shrimp and rice and cheese

Combine milk, ketchup Worcestershire and pepper. Add to shrimp
mixture

Pour into Pam sprayed casserole. Bake until heated through