Mascarpone and Mustard Pasta with Portabella Mushrooms and Roast Chicken

Season the chicken breasts with salt and pepper.
In a large skillet, heat the olive oil over medium-high heat. Add the chicken and cook until golden brown and cooked through, about 6-8 minutes per side, depending on thickness. Remove from the skillet, let rest for a few minutes, then slice thinly.
Bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente. Drain, reserving a cup of the pasta water for the sauce.
In the same skillet used for the chicken, melt the butter over medium heat. Add the mushrooms and cook until they begin to brown and release their moisture, about 5-7 minutes.
Add the shallot and garlic, cooking until fragrant and soft, about 2 minutes.
Deglaze the pan with the white wine, allowing it to reduce by half.
Stir in the chicken broth and bring to a simmer. Reduce the heat to low and whisk in the mascarpone cheese and Dijon mustard until smooth.
Add the grated Parmesan cheese and chopped parsley, stirring until the sauce is creamy and heated through. If the sauce is too thick, thin it with some reserved pasta water. Season with salt and pepper to taste.
Add the cooked pasta to the sauce, tossing to coat evenly. Gently fold in the sliced chicken.
If needed, adjust the seasoning and consistency of the sauce, adding more pasta water if too thick.
Divide the pasta among plates. Garnish with additional Parmesan cheese and fresh parsley.
Serve immediately, accompanied by a light salad and a glass of dry white wine to complement the rich flavors of the dish.