Baked Shrimp Stuffed Pistolettes

shrimp, peeled & deveined, or package of frozen crawfish tails

unsalted butter , divided

of a medium onion , finely chopped

stalk (rib) of celery , finely chopped

of a green bell pepper , finely chopped

green onions , chopped

large clove of garlic , minced

chopped fresh parsley

Campbell's cream of mushroom soup

Velvetta Mexican style cheese

jar of pimentos , optional

freshly ground black pepper

Cajun seasoning (like Slap Ya Mama ), or to taste

Couple dashes of hot sauce

store bought or homemade pistolette rolls

all purpose flour

water