Heat olive oil in a large skillet over medium-high heat. Season the chicken breasts with salt and pepper, then add them to the skillet. Sear for about 5-7 minutes on each side, or until golden brown and cooked through. Remove the chicken from the skillet and set aside.
In the same skillet, add the chopped onion and cook for 2-3 minutes until translucent. Stir in the minced garlic and sauté for an additional 30 seconds until fragrant.
Add the sliced mushrooms to the skillet and cook, stirring occasionally, until they begin to soften and release their juices, about 5-6 minutes.
Pour in the chicken broth and bring to a gentle simmer. Allow it to reduce slightly, about 3-4 minutes.
Lower the heat, and stir in the heavy cream, dried thyme, and Italian seasoning. Mix well to combine and let it simmer for another 2-3 minutes to thicken the sauce slightly.
Return the seared chicken to the skillet, spooning the creamy mushroom sauce over the top. Cook for an additional 2-3 minutes until the chicken is heated through.
Taste and adjust seasoning with additional salt and pepper if needed.
Garnish with fresh chopped parsley before serving.
Notes
Serve with mashed potatoes or pasta for a complete meal.