Peel and devein shrimp; reserve heads and shells for stock. In a small bowl, combine paprika, salt, and cayenne; mix well. Evenly season shrimp with seasoning. Heat olive oil in a skillet over medium-high heat. Once the oil is hot, add one tablespoon butter. Sauté shrimp, in batches, one and a half minutes per side. Transfer shrimp to a warm plate; set aside.

Melt remaining tablespoon butter in skillet. Add sausage; sauté three to five minutes or until fat has rendered and andouille is crispy. Add onions; sauté two minutes. Add garlic, shallot, and green onion bottoms; sauté one minute. Add tomatoes; sauté one minute. Increase heat to high, add stock, and simmer until most of the liquid has evaporated, about five minutes. Add sour cream; stir well.

Return shrimp and fold them into sauce. Cook about three minutes until shrimp are hot and cooked through. Add green onion tops, stir well. Taste; adjust seasoning. Serve hot over hot cooked grits. Garnish with parsley.