Fill your large pot with water and bring it to a boil. Add a generous pinch of salt to the boiling water, then add the 8 oz spaghetti. Cook according to package instructions until al dente, usually about 8-10 minutes. Once cooked, drain the pasta, reserving about 1/2 cup of the pasta water for later.
While the pasta is cooking, heat 2 tablespoons of olive oil in your large skillet over medium-high heat. Add the diced chicken breast and cook for about 5-7 minutes, stirring occasionally, until the pieces are golden and cooked through. Season with a pinch of salt and pepper as they cook.
Lower the heat to medium, add the minced garlic to the skillet with the chicken, and sauté for about 1 minute until fragrant. Be careful not to burn the garlic; it should become aromatic and slightly golden.
Pour in 1 cup of heavy cream and stir to combine with the chicken and garlic. Bring the mixture to a gentle simmer, then add 1 cup grated Parmesan cheese, 1 teaspoon black pepper, and 1/2 teaspoon salt. Stir continuously until the cheese melts and the sauce thickens slightly, about 3-4 minutes.
Add the drained spaghetti to the skillet with the sauce. Toss everything together gently to ensure each strand is beautifully coated. If the sauce is too thick, add a splash of the reserved pasta water to loosen it up until it reaches your desired consistency.
Sprinkle 1/4 cup chopped parsley over the top for a burst of color and fresh flavor. Serve immediately while warm and creamy.
