To make these Sheet Pan Middle Eastern Beef Kebabs, start by preheating your oven to 375 F. Next, prepare the ground beef mixture. Add the white onion, red bell pepper, and garlic to a small food processor and blend until the mixture is liquidy. Transfer it to a bowl and use a paper towel to press out as much moisture as possible.
Add the ground beef to a large bowl, along with the onion, bell pepper, and garlic mixture, the chopped parsley, tomato paste, cumin, paprika, Aleppo pepper, black pepper, and kosher salt. Mix everything together very well until fully incorporated—I like to use my hands for this! Then, transfer the ground beef mixture to a greased quarter sheet pan and spread it into an even, flat layer.
Use a knife to score the beef horizontally and vertically, just like you would see at a restaurant — this will make it easy to cut into individual kebab pieces once they’re done. Transfer the sheet pan to the oven and bake at 375 F for 20 minutes. Then, switch the oven to broil and broil for an additional 4-5 minutes, until the tops are perfectly golden. Remove from the oven and cut the Sheet Pan Middle Eastern Beef Kebabs along the horizontal lines you previously scored.
While the kebabs are in the oven, prepare the sumac salad. Chop the Persian cucumbers, red onion, and roma tomatoes and add them to a bowl. Toss with sumac, red wine vinegar, avocado oil, and kosher salt until well combined. Set aside. Next, make the Greek yogurt sauce. Grate Persian cucumber and press out the liquid using a clean towel or paper towel. Add it to a bowl with Greek yogurt, a squeeze of fresh lemon juice from half a lemon, and kosher salt. Mix to fully combine and set it aside.
Finally, assemble your wraps! Lay out a piece of warm lavash and spread a generous layer of the Greek yogurt sauce down the center. Add 2-3 of the Sheet Pan Middle Eastern Beef Kebabs on top, followed by a scoop of the sumac salad. Fold it up, and enjoy!