Start by seasoning the chicken breasts generously with Cajun seasoning on both sides.
In a large pot of salted boiling water, cook the fettuccine pasta according to package instructions until al dente. Drain and set aside.
In a large skillet, heat the olive oil over medium-high heat. Add the seasoned chicken and cook for about 7-8 minutes on each side, or until the chicken is cooked through and no longer pink in the middle. Remove from the skillet and let rest before slicing.
In the same skillet, lower the heat to medium and add minced garlic. Sauté for about 1 minute until fragrant.
Pour in the heavy cream and bring it to a gentle simmer. Stir in the Parmesan cheese until melted and the sauce is creamy.
Add the cooked fettuccine and baby spinach to the skillet, tossing to coat the pasta in the Alfredo sauce. Cook for another 2-3 minutes until the spinach has wilted.
Slice the rested chicken, and place it on top of the pasta.
Season with salt and pepper to taste, and toss gently to combine.
Notes
Serve in shallow bowls with extra Parmesan and parsley for garnish.