Bring a large pot of generously salted water to a boil, then cook the linguine according to the package directions until al dente. Before draining, reserve 1 cup of the starchy pasta water.

Pat the shrimp completely dry with paper towels, then season them with salt and pepper. Heat 2 tablespoons of the butter and the olive oil in a large skillet over medium-high heat. Add the shrimp in a single layer and cook for 1 to 2 minutes per side until pink and opaque. Transfer the shrimp to a plate.

Reduce the heat to medium, add the garlic and red pepper flakes, and cook for 30 to 45 seconds until fragrant. Pour in the white wine and scrape up any browned bits from the pan. Let it simmer for 3 to 4 minutes until reduced by about half. Stir in the lemon juice and zest and whisk in the remaining 3 tablespoons of butter until the sauce looks glossy.

Add the drained linguine to the skillet along with the cooked shrimp. Toss well, adding reserved pasta water a few tablespoons at a time to loosen the sauce as needed. Stir in the chopped parsley and taste for seasoning.

Divide the shrimp scampi linguine among plates or bowls, garnish with extra parsley, and add grated Parmesan if desired. Serve immediately.