Other additions can be put in, such as sautéed peppers and onions, mushrooms, etc.
You may also use a different grated cheese; one of my favourite alternatives is Red Leicester.
If you are gluten intolerant, you can nix the breaded fillets and go for plain; use another brand of sauce, that is *known* to be "free-from"; and substitute cellophane (rice vermicelli) noodles for the spaghetti.
The brand of sauce I am using (Lidl's "Combino") has all gluten-free ingredients, with no thickeners. It doesn't specify on the label, as to whether it is GF, or not - but I see no wheat products warnings in the allergy information (only "nuts" and "sesame"). Use at your own risk!
This Parmigiana recipe is better than any you will eat in a chain restaurant, I promise ---- and it is super-easy to knock together in a short time, if you tend to keep these ingredients on hand.
Serve this with a toasted garlic baguette, and a green vegetable.
A warning - the brands of products I use, have been chosen through a long process of trial and error! Do not expect for yours to turn out as good as mine, if you use another brand of sauce! I really don't like Dolmio, in particular (my apologies to the makers, and any fans who are reading), and none of their varieties are suitable for this particular dish! Their sauces are far tooooo acidic!