In a shallow dish, combine flour, salt, pepper, and oregano; mix until thoroughly incorporated.

Coat chicken pieces in prepared flour mixture.

In a large skillet, melt butter and heat olive oil over medium heat.

Place chicken in the skillet, cook for 2 minutes per side until lightly browned.

Add sliced mushrooms to the skillet and cook for 5 minutes until tender.

Pour in Marsala wine, cover skillet, and simmer for 10 minutes until chicken is cooked through.

Remove from heat, garnish with parsley if desired, and serve hot.