Heat the olive oil and butter in a large skillet over medium-high heat.
Add the chicken to the skillet and cook until browned on all sides and cooked through, about 5-7 minutes. Remove the chicken and set it aside.
Add the sliced mushrooms to the same skillet and cook until they release their liquid and start to brown, about 5 minutes.
Add the minced garlic to the mushrooms and cook for 1 minute until fragrant.
Pour in the chicken broth and scrape up any browned bits from the bottom of the skillet. Let the broth simmer and reduce slightly for 2 minutes.
Reduce the heat to medium-low. Stir in the heavy cream and Italian seasoning. Let the sauce warm through for 1 minute.
Stir in the Parmesan cheese until the sauce is smooth and slightly thickened.
Return the cooked chicken to the skillet and toss to coat in the sauce. Heat through for 1-2 minutes.
Garnish with fresh parsley before serving.
Notes
Serve this skillet dish over rice, pasta, or with crusty bread to soak up the sauce.
If you prefer a thicker sauce, let the broth reduce longer in step 4 or add 1 teaspoon of cornstarch mixed with 1 tablespoon of cold water before adding the cream.