Heat the olive oil and butter in a large skillet over medium-high heat.
Add the chicken to the skillet and cook until browned and cooked through, about 5-7 minutes. Remove the chicken from the skillet and set aside.
Add the sliced mushrooms to the same skillet and cook until they release their moisture and start to brown, about 5 minutes.
Add the minced garlic to the skillet and cook for 1 minute until fragrant.
Pour in the heavy cream and chicken broth. Bring the mixture to a simmer, scraping up any browned bits from the bottom of the pan.
Reduce the heat to low. Stir in the grated Parmesan cheese, Italian seasoning, and remaining salt and pepper. Stir until the sauce is smooth and slightly thickened.
Return the cooked chicken to the skillet. Stir to coat the chicken and mushrooms in the sauce. Heat through for 2 minutes.
Garnish with fresh parsley before serving.
Notes
Serve this dish over fettuccine, zucchini noodles, or crusty bread to soak up the extra sauce.
For a richer flavor, use fresh grated Parmesan cheese instead of pre-shredded.
You can add a handful of fresh spinach during the last minute of cooking for added greens.