In a heavy pot over medium heat, melt butter. Whisk in flour continuously until mixture turns golden brown, about 5–7 minutes.
Add onion, bell pepper, celery and garlic. Cook until vegetables soften, about 4 minutes.
Stir in tomato paste, then gradually whisk in seafood stock to avoid lumps. Bring to a gentle simmer.
Combine paprika, thyme, oregano, cayenne, garlic powder, onion powder, white pepper and black pepper. Sprinkle into the pot and stir well.
Gently fold in thawed shrimp. Simmer until pink and cooked through, about 5 minutes.
Taste and season with salt. If too thick, add a splash of stock. For a richer stew, stir in a pat of butter.
Remove from heat. Sprinkle chopped green onions and parsley on top.
Ladle over steamed white rice or creamy grits for an unforgettable Southern dinner.