Blend the corn in a blender or food processor until you get a puree. Set aside.

In a large bowl, mix the pre-cooked cornmeal, sugar, salt, mozzarella cheese, milk, the blended corn and melted butter. Start with 1½ cup of milk and then add more if you see that the batter is too thick.

Melt 1-2 tsp of butter in a large pan on medium heat and then pour about ¼-½ cup of the corn batter, depending on how big you want the arepas. Flatten them on top and then shape them into a circle with the help of a spatula. Grill them for 5-7 minutes per side or until they're golden brown. During the last 2 minutes of cooking, you can place 1-2 slices of mozzarella cheese on top so that it has time to melt. Serve immediately.