Grate the onion on the fine side of a box grater. Gather in a clean kitchen towel and squeeze firmly to remove excess liquid. This keeps the kofta from falling apart on the grill.

In a large bowl, combine the ground beef, drained grated onion, minced garlic, chopped parsley, cumin, coriander, cinnamon, Aleppo pepper, and salt. Use your hands to mix gently but thoroughly until just combined. Do not overwork or the kofta will become tough.

Divide the mixture into 8 equal portions. Wet your hands with cold water and shape each portion into a compact oval about 4 inches long and 1.5 inches thick. If using skewers, mold the meat firmly around each skewer. Chill on a plate for 10 minutes to firm up.

Heat a grill pan or outdoor grill to medium-high. Brush the kofta with olive oil. Grill for 4-5 minutes per side, turning carefully with a thin spatula, until deeply browned and cooked through to 160F internal temperature. The outside should have good char marks and the center should feel firm when pressed.

Transfer to a plate and let rest for 3 minutes. Serve warm with warm flatbread, yogurt sauce, sliced tomatoes, and pickled onions.