Cook fettuccine pasta according to package instructions until al dente. Drain and set aside.
In a large skillet, melt butter over medium heat. Add diced chicken breasts and cook until golden brown and cooked through.
Add hacked onion and salt & pepper.
Add minced garlic to the skillet and cook for another minute until fragrant.
Pour in heavy cream and bring to a simmer. Stir in grated Parmesan cheese until melted and sauce is smooth.
Add parsley for about 1 minute before adding the cooked pasta to the skillet and toss to coat in the Alfredo sauce.
