Freeze.
Thaw.
Warm a large skillet over medium heat and add the pork. Fry the pork until the meat is browned and cooked through.
Saute the vegetables until they start to brown, then add the pork back to the pan along with the sauce. Stir to mix.
Note: Shiitake mushrooms have a strong flavor, so if you're not a fan, feel free to substitute your preferred mushroom type.