Pat the chicken cutlets dry with paper towels. Season both sides with salt and pepper.

Heat the olive oil in a large skillet over medium-high heat. Sear the chicken until golden brown and cooked through, about 3–4 minutes per side depending on thickness. Remove from the skillet and set aside.

In the same skillet, add the butter. Once melted, add the mushrooms. Cook, stirring occasionally, until they release their moisture and start to brown, about 5–7 minutes.

Push the mushrooms to the side, add the minced garlic, and cook for about 30 seconds until fragrant.

Pour in the chicken broth and scrape up any brown bits from the bottom of the pan. Stir in the Dijon mustard and thyme.

Lower the heat to medium and pour in the heavy cream. Simmer gently until the sauce thickens, about 3–5 minutes.

Return the chicken to the pan and coat with the sauce. Simmer for 1–2 minutes to rewarm the chicken and meld the flavors.

Taste and adjust with a pinch more salt or pepper if needed. Serve the cutlets with spoonfuls of the creamy mushroom sauce over top.