Ground Beef Gyros

Why I Love This Recipe
I love gyros sandwiches, so here's an easy way to prepare them at home thanks to this TOH Prize Winning Recipe submission. Although I haven't tried this yet, it seems promising, although not authentic.
Ingredients You'll Need
1 carton (8 oz.) plain yogurt
1/3 cup chopped seeded cucumber
2 Tbsp. finely chopped onion
1 garlic clove, minced
1 tsp. sugar
FILLING: 1 lb. ground beef
1 1/2 tsp. dried oregano
1 tsp. garlic powder
1 tsp. onion powder
1 tsp. salt, optional
3/4 tsp. pepper
4 pita breads (6 inches), halved, warmed
3 cups shredded lettuce
1 large tomato, chopped
1 small onion, sliced
Directions
In a small bowl, combine the first five ingredients. Chill.
In a large bowl, combine seasonings, crumble beef over mixture; mix well. Shape into 4 patties.
Grill patties, covered, over medium-hot heat for 6-7 minutes on each side or until a meat thermometer reads 160 degrees F.
Cut patties into thin slices; stuff into pita halves.
Add lettuce, tomato and onion. Serve with the yogurt sauce.