Ingredients:
4 Pita Rounds
Tzatziki
1-2 large onion, chopped
2-3 medium tomatoes, diced
Sliced lettuce, optional
Crumbled feta cheese
Dried Greek Oregano
Directions on How to Make Vegetarian Gyros:
lace a piece of aluminum foil down on a flat surface and put a piece of bread in the center. 
Spread a generous amount tzatziki across the middle of the pita bread. 
Top with chopped onion, diced tomato, and lettuce, if using. 
Sprinkle with feta cheese and drop another spoonful of tzatziki over the top, if desired. 
Also, feel free to sprinkle some dried oregano over the ingredients
Roll the gyro sandwich and wrap it in aluminum foil so it can hold the shape. 
Repeat until you've used up all the bread.