Slice meat against the grain into strips then add to a large ziplock bag.
Add black pepper, allspice, cinnamon, cardamom, za'atar, crushed red pepper, freshly grated nutmeg, dried mint, and salt to a small bowl. Pour oil and vinegar into the bowl and whisk to combine the marinade.
Pour marinade over the beef strips then massage the bag to work the marinade into the meat. Marinate for a minimum of two hours.
Heat a cast-iron skillet over medium high heat for a few minutes. Remove the meat from the marinade and cook in batches. Don't overcrowd the pan. Repeat with the remaining meat.