In a medium bowl, combine the masarepa, sea salt, crumbled Cotija cheese, softened butter, and warm water. Mix until a smooth, non-sticky dough forms, roughly 3-5 minutes.

After the dough has rested, divide it into 8 equal portions. Roll each portion into a ball, then flatten it into a disk about 5 inches wide and ¼ inch thick.

Place a generous amount of shredded mozzarella cheese in the center of each disk. Carefully top it with another flattened disk, sealing the edges well by pressing them together.

Heat a medium skillet over medium-low heat and add oil or butter. Ensure it coats the bottom.

Place the prepared arepas in the skillet, cooking for 4-5 minutes on each side until golden brown.

Once cooked, remove the arepas from the skillet and place them on a plate. Consider spreading a little butter on top while they’re still warm.