Blend the batter by combining sweet corn, egg, all-purpose flour, salt, and granulated sugar in a blender. Blend until mostly smooth with some corn texture remaining. Set aside to rest.

Heat a large skillet over medium heat for about 2 minutes. Add a tablespoon of vegetable oil, swirling to coat the surface.

Spoon about 60 ml of batter onto the skillet for each cachapa, forming a round shape 1/2 inch thick. Cook for 3-4 minutes until golden brown, then flip and cook the other side.

After flipping, place slices of mozzarella in the center of the cachapa and fold it gently; allow about 1 minute for the cheese to melt.

Remove from skillet, top with unsalted butter while warm, and serve immediately.