A tasty and not very spicy breading, combining the taste of tomato and paprika with parsley, garlic and onion, the result you want to obtain is a tasty mixture but in which the 'aromaticity with even sweetish tones compared to the aggressiveness of very spicy blends.
The secret of gratin and breading
You probably know both how to make breadcrumbs and how to cook a gratin dish but perhaps you don't know the secret on which both depend (and not just these two, but also many other things in the kitchen ) and therefore why you take certain steps. It might be useful to know this in case you think of experimenting instead of following a recipe step by step. Both the crunchy golden crust that envelops a breaded cutlet and the crust that forms on the surface of a gratin dish are the result of a series of rather complex chemical processes that go by the name of Maillard reaction (from the name of the chemist and doctor French Louis Camille Maillard). You don't have to study the formulas, the useful thing to know is that this is the result of the reaction between sugars and proteins, so when you prepare a gratin dish there must always be both (remember that flour and breadcrumbs are carbohydrates, i.e. complex sugars), here because in particular in the recipes of vegetable gratins in which (unlike those of meat and fish) the proteins are not already present in the dish to be gratinated, you will find the addition of grated parmesan. And what about the breading? Now you have understood one of the reasons why you dip what you are breading in the egg (someone suggests using milk as an alternative) which contains proteins.
Where to use sweet Mexican gratin breading
Paprika is a spice that is obtained from dried peppers, there are various degrees of spiciness because the peppers used can also be chili peppers but in general paprika is not very spicy and let you savor the taste of the pepper. If we add to this the taste of tomato, this is why we called this sweet Mexican breading, Mexican because we need to remember that even if we Italians now consider them "our stuff", both peppers and tomatoes come from the "New World". The first use that comes to mind is breading meat, we can't invent red breading or tomato breading, it's a recipe you can easily find, for example for breading cutlets. A use that is instead suggested by the adjective sweet is to use it if you are gratinating bitter vegetables, obviously to dilute their bitterness.