Grate the melted cheese on a coarse grater, you can also add a hard one to the pie, but with a melted taste more tender. Add the fried onion, 2.5 eggs, salt, pepper to the cheese and mix well. A lot of eggs should not be added, because the filling will be liquid and will spread, the cake will be difficult to close (except if you cook in a baking dish). Leave the yolk of one egg to lubricate the pie before baking in the oven.