If your shrimp is frozen, thaw and peel before beginning.
Bring a pot of water to a boil for the fettuccine. Once boiling, add the fettuccine and boil until tender (7-10 minutes). Reserve a ½ cup of the starchy water before draining the pasta.
While the fettuccine is boiling, pat dry the peeled shrimp with a paper towel and season with salt and pepper.
Add 1 tablespoon butter to a large skillet over medium heat. Once hot, add the shrimp and cook for 1-2 minutes on each side until opaque and pink.
Reduce heat to medium-low, add 1 tablespoon butter and minced garlic to the skillet, and sauté for 1-2 minutes until fragrant.
Add heavy cream to the skillet and whisk to dissolve any browned bits. Allow to simmer.
Whisk in Parmesan until melted, then season with salt and pepper.
Add cooked fettuccine and shrimp back to the skillet, tossing to coat in sauce. Add reserved pasta water if needed.