In a large mixing bowl, combine 2 cups of masarepa, a pinch of sea salt, ½ cup of crumbled Cotija cheese, and 2 tablespoons of softened butter. Gradually add about 1½ cups of warm water while mixing until a smooth, non-sticky dough forms.

Knead the dough for about 2-3 minutes until it's well combined and the texture is pliable.

Cover the dough with a clean kitchen towel and let it rest for 10 minutes.

Wet your hands to prevent sticking, then divide the rested dough into 8 equal portions. Roll each portion into a ball, then flatten each ball into a round disk about 5 inches in diameter.

Place a generous amount of shredded mozzarella cheese in the center of half of the disks. Then, fold the remaining disks over the filled ones and pinch the edges to seal tightly.

Heat 2 tablespoons of oil or butter in a skillet over medium heat. Once hot, add the filled arepas and cook for 4-5 minutes on one side until golden brown and crisp.

Carefully flip them over and cook an additional 4-5 minutes on the other side.

Once cooked, remove the arepas from the skillet and place them on a paper towel to absorb any excess oil. Serve warm.