Peel and devein 1 pound raw jumbo shrimp if needed, then pat dry with paper towels.

Melt 2 tablespoons of the unsalted butter in a 12-inch straight-sided skillet or Dutch oven over medium-high heat. Add the shrimp in a single layer and season with ½ teaspoon of the kosher salt. Cook undisturbed until starting to brown on the bottom and they release easily from the pan, about 2 minutes. Flip the shrimp and cook until just cooked through, about 1 minute more. Transfer to a bowl or plate.

Melt the remaining 1 tablespoon unsalted butter in the skillet. Add 6 to 7 ounces sliced andouille sausage and cook, stirring occasionally, until starting to brown in spots, about 3 minutes. Stir in 1 thinly sliced medium green bell pepper, 1 finely chopped small yellow onion, and 2 thinly sliced garlic cloves. Cook, stirring occasionally, until the vegetables start to soften and the sausage is browned in spots, about 5 minutes.

Stir in 1 (14.5-ounce) can drained fire-roasted diced tomatoes, 3 cups water, 1 ¼ cups heavy cream, 12 ounces dried linguine pasta, 2 tablespoons Cajun seasoning, and the remaining ¼ teaspoon kosher salt. Bring to a boil over high heat. Continue to boil, turning the pasta frequently with tongs, until the pasta is al dente and the liquid has reduced to a thickened, creamy sauce, 8 to 11 minutes.

Remove the skillet from the heat. Add 2 ounces grated Parmesan cheese and 2 teaspoons vinegar. Toss with tongs until well combined and the cheese is melted. Taste and season with more kosher salt as needed.

Return the shrimp and any accumulated juices to the pan and toss to combine. Serve garnished with more grated Parmesan and finely chopped fresh parsley leaves if desired.