In a skillet over medium heat, warm a small amount of oil and sauté the chopped onions until soft and translucent. Add the minced beef and cook thoroughly, breaking it up with a spatula until browned and no longer pink. Season with salt, black pepper, and cinnamon. Once cooked, remove from heat and let it cool to room temperature.
In a large mixing bowl, combine the cooled beef with diced tomatoes, green peppers, spring onions, and leeks. Crack in the eggs, sprinkle in the cumin, and add more salt and pepper if needed. Mix everything well until the filling is fully blended.
On a clean surface lightly greased with vegetable oil, take one paratha sheet and stretch it gently using your hands into a large square. Keep the center slightly thicker to support the filling and avoid tearing during folding.
Spoon about 60 ml of the prepared filling into the center of the stretched dough. Top with a handful of shredded mozzarella and cheddar cheese mix. Carefully fold each corner of the dough inward over the filling, forming a sealed square parcel.
Preheat a non-stick pan over medium heat and add a touch of oil. Place the folded mutabbaq seam-side down in the pan and cook until golden and crisp, then flip and cook the other side to the same golden hue.
Repeat the process for the remaining paratha sheets and filling. Serve hot with fresh lemon wedges on the side for a bright, citrusy contrast.