Preheat oven at 400-degree Fahrenheit and prepare a baking sheet with a greased parchment paper. In a mixing bowl combine all the marinade ingredients (except tempeh and mushrooms). Mix it well until all the spices and well blended.
Bring about 3 cups pf water to a boil and drop tempeh slices in it. Let it boil for 2-3 minutes and drain using a colander. Place the colander with tempeh under cool running water for 30 seconds.
Now, take each slice of tempeh and rub them nicely on all sides with the marinade.
Then, place each tempeh on one side of the sheet pan/baking sheet.
Then,in the same mixing bowl, toss shiitake mushroom with the leftover marinade.
Now, place the mushrooms on the second side of the baking dish.
In the same mixing bowl combine all the ingredients for zucchini and mix well by along with scraping the leftover marinade or any spices.
Then,place them on the third side on the baking dish.
Place the baking dish in the middle rack of the oven and bake it for 45 minutes. Take it out place it on a flat surface.
Now, warm up the pita bread and place 3-4 tempeh slices at its center. Then, place about 2 tbsp of mushrooms, followed by a tablespoon of zucchini. Then, top it with tzatziki sauce.
Now, lettuce, onions and red bell pepper.
Then, roll it gently and wrap in a butter paper,parchment paper or simply in aluminum foil so the wrap does not fall apart.Serve immediately.