Season the Chicken: Pat the chicken breasts dry with paper towels. Season both sides with salt and pepper. This step helps the chicken brown nicely and keeps the flavor balanced.
Sear Until Golden: Heat olive oil in a large skillet over medium heat. Add the chicken and cook for about 5 to 6 minutes per side until golden and cooked through. Transfer the chicken to a plate and cover loosely.
Build the Base: Lower the heat slightly and add butter to the same pan. Stir in the shallots and cook until soft and fragrant, about 2 minutes. Add garlic and stir briefly so it does not burn.
Cook the Mushrooms: Add the sliced mushrooms to the skillet. Cook until they soften and release their moisture. Stir often so they pick up the browned bits from the pan.
Deglaze with Brandy: Carefully pour in the brandy. Let it simmer while scraping the pan to lift all the flavor. Cook until the liquid reduces slightly and the sharp alcohol smell fades.
Create the Sauce: Stir in chicken broth, Dijon mustard, and Worcestershire sauce. Let the mixture simmer for a few minutes until it starts to thicken and look glossy.
Add Cream and Lemon: Pour in the heavy cream and stir gently. Add the lemon juice and let the sauce simmer until smooth and lightly thickened.
Finish and Serve: Return the chicken to the pan and spoon sauce over the top. Sprinkle with fresh parsley and let everything warm together for a minute before serving.
