Prepare fettuccine pasta al dente according to the instructions on the box—reserve 1 cup of pasta water. Once the pasta is cooked and drained, rinse it with cold water and set it aside.

Pat the chicken breasts dry with paper towels. Cut the breasts into cubes. Heat the olive oil or butter in a large skillet over medium-high heat. Add the cubed chicken breasts to the skillet once the oil is hot (but not smoking). Season with ½ teaspoon of Kosher salt and ¼ teaspoon of ground black pepper. Cook the chicken for about 5 - 7 minutes, stirring occasionally so they are evenly cooked. The chicken should reach an internal temperature of 165°F (75°C) and be golden brown. Add 2 minced garlic cloves and saute with chicken until fragrant, about 30 seconds. Once cooked through, remove the chicken from the skillet.

Bring a large pot of salted water to a boil. Cut the broccoli into bite-sized florets. Add the broccoli florets to the boiling water. Cook for 2 - 3 minutes until the broccoli is bright green and just tender but still crisp. Drain the broccoli and set it aside.

Add 8 tablespoons unsalted butter to a medium saucepan and stir until melted. Add 3 cloves of minced garlic and simmer until fragrant, about 30 seconds. Then add 2 cups of heavy cream and 1 ½ cups of grated parmesan cheese and bring to a simmer over low-medium heat, whisking constantly. You will want the sauce to be bubbly, but be careful not to overheat as it will boil over easily.

Allow the sauce to simmer for about 5 minutes, then slowly add the cooked fettuccine to the skillet and toss the pasta so that the alfredo sauce coats it. Add some of the pasta water and stir to thicken. Add the cubed chicken and cooked broccoli to the pasta and heat until warm. Remove from heat. Serve and enjoy!