Prep the chicken: Pat chicken dry with paper towels. Season both sides with salt and pepper. If using breasts, slice them in half horizontally to make cutlets for quicker, more even cooking.

Heat the skillet: Set a large skillet over medium-high heat. Add the oil and butter. When hot and shimmering, add the chicken in a single layer.

Brown the chicken: Cook without moving for 4–5 minutes until golden. Flip and cook another 3–4 minutes, or until just cooked through. Transfer to a plate and tent loosely with foil.

Sauté the mushrooms: Add sliced mushrooms to the same skillet. Sprinkle with a pinch of salt. Cook 5–7 minutes, stirring occasionally, until they release moisture and take on a deep golden color.

Add aromatics: Stir in chopped shallot and minced garlic. Cook 1–2 minutes until fragrant, being careful not to burn the garlic.

Deglaze and season: Pour in the chicken broth, scraping up any browned bits. Stir in thyme, parsley, and a pinch of red pepper flakes if you like heat. Simmer 2–3 minutes to reduce slightly.

Add cream: Lower heat to medium. Pour in heavy cream and stir. Simmer gently for 3–4 minutes, until the sauce thickens enough to coat a spoon. If using, mix in Dijon or lemon juice and Parmesan for extra tang and body.

Return chicken to the pan: Nestle the chicken back into the sauce with any juices from the plate. Simmer 2–3 minutes until heated through and the sauce lightly clings to the chicken.

Taste and adjust: Season with more salt and pepper as needed. If the sauce is too thick, add a splash of broth. If too thin, simmer another minute.

Garnish and serve: Sprinkle with fresh parsley or chives. Serve hot with cauliflower rice, sautéed spinach, or a crisp green salad.