In a large skillet, heat olive oil over medium heat. Add sliced mushrooms and cook until they are golden brown and soft, about 5-7 minutes. Remove from skillet and set aside.
In the same skillet, add butter and minced garlic. Sauté until fragrant, about 1 minute.
Pour in the chicken broth, scraping up any brown bits from the pan, then add heavy cream. Stir well and simmer for 5-7 minutes, allowing the sauce to thicken.
Stir in the Parmesan cheese and season with salt and pepper to taste. Continue to cook until the sauce reaches a creamy consistency.
Add the sautéed mushrooms back into the sauce, stirring to coat them in the creamy mixture. Simmer for another 2-3 minutes until fully combined.
Remove from heat and serve the creamy mushroom sauce over pasta, chicken, or your favorite dish.