Ingredients

For the Chicken

• 680 g / 1½ pounds boneless, skinless chicken breasts
• 1 tablespoon extra-virgin olive oil
• ½ teaspoon fine sea salt
• ½ teaspoon freshly ground black pepper

For the Mushrooms

• 340 g / 12 ounces cremini or button mushrooms, cleaned and sliced
• 1 tablespoon extra-virgin olive oil
• 15 g / 1 tablespoon unsalted butter
• A small pinch of fine sea salt

For the Pasta and Sauce

• 340 g / 12 ounces dry fettuccine
• 45 g / 3 tablespoons unsalted butter
• 3 garlic cloves, minced finely
• 360 ml / 1½ cups heavy cream
• 140 g / about 1½ cups finely grated Parmigiano-Reggiano
• ½–1 cup reserved hot pasta water
• Fine sea salt and freshly ground black pepper, as needed
• 2 tablespoons chopped flat-leaf parsley, optional

Preparation

1. Prepare the chicken. Slice each breast horizontally into thinner cutlets or pound the thickest portions to an even ½-inch thickness. Pat dry and season with salt and pepper.
2. Sear until browned. Heat 1 tablespoon olive oil in a broad skillet over medium-high heat. Cook the chicken without crowding until deeply golden and the thickest portion reaches 165°F / 74°C, approximately 4–6 minutes per side depending on thickness. Transfer to a plate and rest before slicing.
3. Brown the mushrooms. Add the remaining olive oil and 1 tablespoon butter to the skillet. Cook the mushrooms in one uncrowded layer, working in batches when necessary. Allow them to brown before stirring. Season lightly and transfer to a bowl.
4. Cook the fettuccine. Bring a large pot of well-salted water to a boil. Cook the fettuccine until just al dente. Before draining, reserve at least 1 cup of the hot, starchy water.
5. Begin the sauce. Lower the skillet heat to medium-low and melt the remaining 3 tablespoons butter. Add the garlic and cook for only 30–45 seconds, until fragrant but not browned.
6. Add the cream. Pour in the heavy cream and bring it to a gentle simmer. Cook for 3–4 minutes, stirring frequently, until it reduces slightly. Do not boil aggressively.
7. Emulsify with cheese. Reduce the heat to low. Add the Parmigiano-Reggiano gradually while whisking. Add small splashes of hot pasta water until the sauce becomes smooth, glossy, and loose enough to coat the pasta.
8. Toss the fettuccine. Add the drained pasta directly to the skillet and toss continuously for 1–2 minutes. The sauce will thicken as it clings to the fettuccine.
9. Return the chicken and mushrooms. Slice the rested chicken across the grain. Fold it and the browned mushrooms into the pasta, reserving a few pieces for the top. Add more pasta water whenever the sauce tightens.
10. Finish and serve. Taste for salt and black pepper. Divide among warm bowls and finish with Parmigiano-Reggiano, parsley, and the reserved chicken and mushrooms. Serve immediately.