Season chicken breasts with salt and pepper on both sides.
Dredge each piece in flour, shaking off excess to ensure a thin coating.
Heat olive oil in a large heavy-bottomed skillet over medium-high heat.
Sear chicken for 6 minutes per side or until internal temperature reaches 165 degrees Fahrenheit and exterior is golden brown.
Remove chicken from skillet and transfer to a warm plate.
Add butter to the same skillet and sauté mushrooms for 5 minutes until moisture has evaporated and they are browned.
Incorporate minced garlic and thyme, cooking for 60 seconds until aromatic.
Pour in chicken stock to deglaze, scraping the fond from the bottom of the pan.
Add heavy cream and simmer for 3 to 4 minutes until the sauce reduces and thickens.
Lower heat to minimum and whisk in Parmesan cheese until fully incorporated and smooth.
Return chicken to the pan to coat with sauce before serving.