Prepare the kifta. To a food processor, add the parsley, onions, bell pepper, green onions and garlic. Pulse together until everything is minced into small pieces. Add the ground beef to a mixing bowl along with the chopped veggies. Add the salt, pepper, allspice, coriander and 7 spice and mix well.
Make the cucumber yogurt sauce by adding the yogurt to a bowl with the chopped cucumbers. Grate in the garlic (very important that its grated and not minced), crush in the dry mint with your hands and sprinkle in some salt. Mix everything together well and set aside. If you’re using Greek yogurt and find the sauce to be too thick, mix in 1 Tablespoon of water at a time till you get your desired consistency.
Form into patties slightly larger than the buns you’re using – the meat shrinks as it cooks and doing this will ensure that your burger will cover the entire bun once you build your burger. I like thinner burgers (about ¼ inch thick) but make them your desired size. Add the burgers to a griddle, cast iron, or grill. Let them cook halfway through and develop a char, flip and cook on the other side to develop a char and reach desired doneness. Remember that the thicker the burger, the longer they’ll take to cook.
Toast up the burger buns, place a patty on the bottom bun, top with the cucumber yogurt sauce, then the sumac onions, sliced tomatoes, sliced cucumbers, spread some harissa on the top bun before placing it on top and enjoy!