Heat 2 tablespoons of olive oil in a wide ovenproof pot. Add the beef and sear over medium-low heat, about 2 minutes per side. Stir in the onions, date syrup, pomegranate concentrate, salt, and pepper. Add boiling water to cover, bring to a simmer, then cover the meat with parchment paper and seal the pot with a lid.
Transfer to a 320°F/160°C oven and cook until the beef is tender and shreds easily, 3 to 4 hours.
Remove from the oven, transfer the beef and caramelized onions to a bowl, and mix with 3 tablespoons of the cooking liquid. Shred with forks or by hand. Let cool completely. Adjust seasoning if needed.
On a work surface, lay out a rectangle of phyllo dough. Place the cooled beef mixture in the center, leaving clean borders. Cover with another rectangle of dough, trimming to fit, and seal edges tightly. Cut slits or a lattice design if desired. Brush with the beaten egg.
Bake at 355°F/180°C convection for 25 to 30 minutes, or until golden and crisp, taking care not to dry the filling.
Remove from the oven, drizzle with honey, scatter pomegranate seeds, and sprinkle parsley before serving.