Step 1: Cook the linguine according to package directions until al dente. Before draining, reserve about 1 cup of the starchy pasta water. Drain and set aside.
Step 2: While pasta cooks, pat chicken cubes dry with paper towels. In a medium bowl, toss chicken with 1 tablespoon of olive oil and Cajun seasoning until evenly coated.
Step 3: Heat the remaining 1 tablespoon of olive oil in a large skillet or pan over medium-high heat. Add the seasoned chicken and cook for 5-7 minutes, stirring occasionally, until browned and cooked through. Remove chicken from skillet and set aside.
Step 4: In the same skillet, reduce heat to medium-low. Add butter and let it melt. Add minced garlic and sauté for 1 minute until fragrant, being careful not to burn it.
Step 5: Pour in the heavy cream, stirring constantly. Bring to a gentle simmer, but do not boil. Cook for 2-3 minutes, allowing it to thicken slightly.
Step 6: Remove the skillet from the heat. Gradually stir in the grated Parmesan cheese until completely melted and the sauce is smooth. If the sauce is too thick, add a little reserved pasta water, a tablespoon at a time, until desired consistency is reached. Season with salt and pepper to taste.
Step 7: Add the cooked linguine and the cooked Cajun chicken back into the skillet with the Alfredo sauce. Toss gently to coat everything evenly.
Step 8: Serve immediately, garnished with extra Parmesan cheese and fresh chopped parsley.