Combine the Marinade ingredients in a large bowl and mix well. Add the beef and mushroom and mix until well coated. Allow to marinate for 20 minutes.
To make the Seasoned Spinach, bring a saucepan of water to a boil and blanch the spinach for 1–2 minutes. Remove from the heat, rinse in cold water and drain. Squeeze out any excess water from the spinach. Place t