Bring a large pot of salted water to a boil and cook the fettuccine according to package instructions, about 8 minutes. Drain and do not rinse.

Melt 2 tablespoons of butter in a skillet over medium heat. Season shrimp with salt and pepper, then cook for 2-3 minutes on each side until pink and opaque. Remove and set aside.

In the same skillet, add the remaining tablespoon of butter. After it melts, add garlic and sauté until fragrant. Pour in heavy cream and bring to a simmer. Gradually stir in Parmesan until melted and smooth.

Add cooked fettuccine and sautéed shrimp back to the skillet. Toss to coat in the sauce. If too thick, add reserved pasta water to reach desired consistency.

Plate the fettuccine Alfredo and garnish with parsley and extra Parmesan. Serve immediately.