Make the dough: In a bowl, mix the cornmeal with warm water and salt until a soft dough forms. Let it rest for 5 minutes.
Form the arepas: Divide the dough into 6 portions, shape into balls, and flatten into thick discs.
Cook: Cook the arepas on a griddle or skillet over medium heat for 2–3 minutes on each side until golden. You can then bake them for a few minutes if you prefer them crispier.
Fill: Slice the arepas open on one side, fill with the hot shredded beef, and top with grated cheese.