In a shallow dish or bowl, mix together the flour, salt, pepper and oregano.
Dredge chicken pieces lightly in flour mixture, shaking off excess.
In a large skillet, melt butter and oil over medium heat.
Place chicken breasts in the pan, and lightly brown.
Turn over chicken pieces, and add mushrooms.
Pour in wine and stock.
Cover skillet; simmer chicken 10 minutes, turning once, until no longer pink and juices run clear.
Cook's Note: To cook the breast faster, consider pounding them to a ¼-inch thickness. Place breast between two sheets of wax paper, and pound with kitchen mallet.
Recipe by Pizza Today at https://staging-pizzatoday.kinsta.cloud/recipes/entrees/chicken-marsala