1. Combine all the ingredients, excluding the hard cheese, in a bowl and stir until a smooth dough forms.
2. Heat a frying pan to medium and drizzle with oil.
3. Add the mixture and let it cook for a few minutes on each side.
4. Grate the hard cheese and add it to half of the mixture.
5. Fold, forming the sandwich.
6. Remove from the heat and serve the cheese once it has melted.