Heat half of the butter and half of the olive oil in a heavy skillet over medium high heat.
Season the chicken tenders and then sear in batches until browned on all sides. Remove from skillet and set aside.
Add the rest of the butter and oil to the skillet and cook the mushrooms until they are browned and crispy.
Add the garlic, herbs and chicken stock and deglaze the pan, scraping all of the good stuff from the bottom of the pan.
Add the cream and sour cream and simmer until sauce starts to thicken. Do not boil, as cream could split.
Return the tenderloins to the pan and toss through the sauce. Cook for five more minutes. or until internal temperature of the chicken is 165 degrees F.
Store, covered, in the refrigerator for up to 5 days.