Heat the olive oil in a small cast iron skillet over medium heat.
Dry the shrimp with a paper towel and season with salt, pepper, and old bay seasoning.
Toss the shrimp in the hot oil and cook for about 3-4 minutes per side or until pink.
Remove the skillet from the burner to cool.
In a large mixing bowl, combine 3/4 cup mayonnaise1 stalk Celery, diced1 Green onion, diced1 tbsp Chives, chopped1 tsp Dill, dried1 tsp Old Bay seasoning1/2 tsp Black pepper1/4 tsp Sea salt
Add the shrimp to the mixing bowl, stir, and refrigerate while preparing the remaining ingredients.
Turn the broiler on high.
Cut the hoagie buns in half lengthwise, spread the butter over the entire inside of the buns and sprinkle with garlic salt.
Place the buns on a sheet pan and broil for 3-4 minutes, or until the butter is melted and they become a golden toasty top.
Remove the buns from the oven and place one on each plate.
Place one romaine leaf on each bun and top with 1/4 of the shrimp salad on each sandwich.