Bring a large pot of salted water to a boil. Add the spaghetti and cook according to the package instructions until al dente. Drain and set aside.
2. Prepare the Alfredo Sauce
In a medium saucepan, melt the butter over medium heat. Add the minced garlic and sauté for about 1 minute, until fragrant.
Pour in the heavy cream and bring to a gentle simmer. Stir occasionally until the cream is heated through.
Gradually add the shredded Parmesan cheese, stirring continuously until the cheese is melted and the sauce is smooth.
Season with salt, black pepper, and nutmeg (if using). Reduce heat to low and let the sauce simmer for 2-3 minutes. Remove from heat and set aside.
3. Cook the Chicken and Mushrooms
Heat olive oil in a large skillet over medium-high heat.
Add the chicken pieces to the skillet, season with salt and pepper, and cook for about 5-7 minutes, or until the chicken is cooked through and golden brown. Remove the chicken from the skillet and set aside.
In the same skillet, add the sliced mushrooms and cook for about 3-4 minutes, until they are tender and have released their juices.
Pour in the chicken broth and cook for an additional 2 minutes, scraping up any browned bits from the bottom of the skillet.
4. Combine Everything
Return the cooked chicken to the skillet with the mushrooms and broth. Stir to combine.
Pour the prepared Alfredo sauce over the chicken and mushrooms. Stir until everything is well coated.
Add the cooked spaghetti to the skillet and toss to combine, ensuring the pasta is evenly coated with the sauce.
5. Serve
Divide the creamy chicken and mushroom Alfredo spaghetti among serving plates. Garnish with chopped fresh parsley and extra Parmesan cheese, if desired.
Notes and Tips
Chicken Variations: You can use chicken thighs instead of breasts for a richer flavor, or even substitute with grilled chicken for a different twist.
Mushroom Choices: Feel free to mix different types of mushrooms, such as shiitake or portobello, for added depth of flavor.
Creaminess: If you prefer a thicker sauce, reduce the heavy cream slightly or add more Parmesan cheese. For a lighter version, you can use half-and-half instead of heavy cream.
Make-Ahead: The Alfredo sauce and chicken mixture can be prepared ahead of time and stored in the refrigerator. Reheat and combine with freshly cooked spaghetti just before serving.