Pat chicken dry and season both sides with salt, pepper, and garlic powder. Heat oil in a large skillet over medium-high heat. Add chicken and sear for 5 to 6 minutes per side, until golden and cooked through (165°F internal temp). Transfer to a plate and rest while you prepare the pasta and sauce.
Boil the Pasta
Bring a large pot of salted water to a boil. Add fettuccine and cook until al dente, according to package directions. Reserve 1/2 cup pasta water, then drain and set aside.
Make the Alfredo Sauce
While the pasta cooks, melt butter in a large saucepan over medium heat. Add garlic and cook for 1 minute, until fragrant. Whisk in cream, salt, and pepper. Simmer for 2 to 3 minutes. Take off the heat and whisk in parmesan until melted and smooth.
If needed, thin the sauce with about 1/4 cup of reserved pasta water to start. You can add up to the 1/2 cup, if needed.
Combine Chicken Alfredo
Slice the chicken into crosswise strips. Add drained fettuccine and chicken to the sauce and toss to coat and heat through in the large pot. Taste and adjust seasoning if needed. Serve topped with a sprinkle of chives or parsley.
Video
Notes
Parmesan Cheese: Always use freshly-grated parmesan from a block, not pre-shredded. The anti-caking agents in pre-shredded cheese make the sauce grainy.
Sauce Tip: Remove the pan from heat before adding the cheese. This keeps the sauce creamy and prevents graininess from overheating.
Pasta Water: Reserve about 1/2 cup of pasta water before draining. The starchy water helps thin the sauce and helps it cling to the pasta.
Chicken: Let the chicken rest before slicing. This keeps it juicy. Use a thermometer to ensure it reaches 165°F.
Storage: Store leftovers in an airtight container in the fridge for up to 3 days. Add a splash of cream when reheating.