Step 1

Melt 1/2 stick butter in a large skillet. Once bubbling, add chopped onion and celery. Saute for 3-5 minutes, until translucent. Add garlic and cook for another 30 seconds.

Step 2

Stir flour into the veggie mixture; allow the flour to cook for a minute or two. Whisk in heavy cream until a thick sauce forms. Stir in tomato paste, chicken stock, worcestershire sauce, and seasonings. Fold in shrimp and 1/2 cup parmesan cheese.

Step 3

Pour shrimp mixture into a greased 9x13" baking dish. Set aside.

Step 4

In a separate bowl, mash together potoatoes, butter, sour cream, parmesan cheese, milk, cajun seasoning, and salt. Spread this mixture on top of shrimp base.

Step 5

Bake at 350 degrees for 30-35 minutes, until shrimp mixture starts to boil. Turn on the broiler and bake for an additional 5 minutes to brown tops of potatoes.

Step 6

Serve topped with green onions.