I've had various tasty arepas before, usually the storebought kind, and I'd always get frustrated because the store by me only sells the ones that are just corn cakes with some cheese in the dough, not the kind I got in my freshman year of college that had the corny, cheesy dough but were chock full of real gooey cheese in the middle! So I looked at few recipes and decided to make my own-- any kind of grated/shredded super-hard cheese will work for the dough, like parmesan, pecorino romano, or even nutritional yeast in a pinch. Manchego is the best to use though. Mozzarella and/or monterey jack are best for the filling, I used mozzarella because I had some to use up. The kind that you cut would also work; 2 cups is an estimate (and kinda an overestimate.)