Preheat oven to 325 degrees. Add ground beef, onion, garlic, marjoram, rosemary, salt and pepper to a food processor. Process for about 1 minute, until it forms a paste.
Scrape out the mixture onto a lined jelly roll pan (any pan with sides). Press the mixture firmly into a rectangle about 1-2 inches thick. Make sure to firmly pack it together.
Bake for 15-20 minutes. Don't over bake or the meat will be dry. The internal temp should be 175.
Remove meat from the oven, and let stand for 10 minutes before slicing.
Serve on a pita topped with lettuce, red onion, tomatoes and Tzatziki Sauce.
To prepare the Tzatziki Sauce Combine all of the ingredients in a bowl, and mix until well combined.