Season chicken breasts on both sides with salt and pepper. Heat olive oil in a large skillet over medium-high heat. Add chicken and cook for 5-7 minutes per side, until golden and cooked through (internal temperature reaches 165°F). Remove from skillet and set aside to rest.

While the chicken cooks, bring a large pot of heavily salted water to a boil. Add the fettuccine and cook according to package directions until al dente. Reserve 1 cup of the pasta water before draining.

In the same skillet, reduce heat to medium-low. Add the butter and melt it. Add the minced garlic and cook until fragrant, about 30 seconds.

Slowly pour in the heavy cream, whisking to combine with the butter and garlic. Bring to a gentle simmer and let it cook for 2-3 minutes, allowing it to thicken slightly. Do not boil.

Remove the skillet from the heat. Gradually add the freshly grated Parmesan cheese, whisking constantly until the cheese is fully melted and the sauce is smooth.

Add the drained fettuccine to the skillet with the sauce. Toss well to coat all the pasta. If the sauce is too thick, add a splash of the reserved pasta water until it reaches your desired consistency.

Slice the rested chicken breast against the grain. Serve the pasta topped with the sliced chicken and a garnish of fresh parsley.