Creamy Shrimp Scampi Sauce

1. In a cast-iron skillet, melt two tablespoons butter over medium heat and sear shrimp for about 1 minute on either side until just cooked through and starting to turn pink. Season with salt and pepper to taste. Transfer to a plate and reserve. 2. Return the skillet to medium heat and melt the remaining butter. Sauté shallot until translucent, then add garlic and sauté until fragrant, about 1 minute. Season with salt and pepper to taste. 3. Deglaze the pan with dry white wine (or broth) and reduce by half. 4. Reduce heat and simmer heavy cream, stirring all the while. Sprinkle in Parmesan and stir until melted. Once thickened, squeeze lemon and adjust seasonings to taste. 5. Add shrimp to the sauce and stir in fresh parsley. Heat until shrimp are cooked through, then serve over steaks or linguine or over toasts as an appetizer. Garnish with additional parsley and crushed red pepper, if desired.