Whatever method you use, the key is low, slow heat. You want to cook slowly in order to drive off excess moisture from the interior as the exterior gets slowly browned. A well-made arepa should take at least ten to fifteen minutes to cook.
Young Colombian cheese tend to be slightly sour and have a relatively high melting point, which is necessary when you incorporate it into the arepa dough. You don’t want it to melt all over the place while you cook. If you can find traditional Colombian farmer’s cheese, feta, cotija, ricotta salata, or even a relatively young Pecorino Romano or Parmigiano-Reggiano will work (if using the latter two, cut the amount called for in half). Cheese-Stuffed Thick Arepas
Even more intense than basic cheesy arepas are arepas made with a thick layer of melty cheese stuffed right into the middle. I first had these at an outdoor stand in the small town of La Calera, about an hour’s ride outside of Bogotá. They were cooked on a little rotating stone pedestal near an open coal fire. Smoky, cheesy, and delicious.