Combine flour, water, and salt in a large bowl and mix them well. After you make the dough; close the bowl top with a moisturized piece of cloth or towel and let the dough rest about 20 minutes.
While the dough is resting, combine the ground beef, grated mozzarella, grated onion, salt, ground black pepper, parsley leaves.
After the dough rest, put some flour to the counter surface and divide the dough to 8 equal pieces. Take the first piece of the dough you divide and roll it until it has 3-4 mm thickness (make thin) and 35-40 cm radius with a rolling pin.
Take 1 spoon of filling mixture and spread it on to the 20 cm radius dough sheet. Close the dough sheet sides and top and bottom. Apply the method to the remaining dough sheet pieces.
Heat the flat top grill or electric griddle at medium heat. Brush the base of the flat top grill with butter. And then put the closed dough sheets on the flat top grill (two by two OR three by three according to the size of your flat top grill). Flip the dough sheets at every 30 seconds and brush the flipped side of the dough sheets with butter. Cook them until both sides of the dough sheets have a golden color.
Tip: Garnish it with lemon wedges.