Combine sliced steak, oregano, Cavender, salt and pepper in a Ziploc bag.
Mix until the seasoning has evenly coated the steak.
In a cast iron skillet, over medium heat, heat 1 tablespoon oil.
Sear sliced steak in batches, for 1 to 2 minutes per side, depending on how you like your steak.
Do not over crowd the pan.
Add 1 tablespoon of oil if the pan gets too dry.
Once the steak is cooked, throw your mushrooms in the pan and sauté until tender.
Assemble the pitas with steak, onions and mushrooms.