If I were to make an Italian homemade pie that can work for almost all occasions (i.e. for kids because of no coffee/alcohol etc.) I'd think of a jam crostata. It's a buttery dough (pasta frolla) that is thinly rolled, filled with jam or custards and topped either with stripes/other patterns of the same dough or fruit or just nothing.
There are many recipes for pasta frolla, depending on how crumbly/compact/airy it has to be. The following video is just an example, but it's about a general principle in there that I'd like to ask about.
This Italian pastry chef, quite a reference in the field I'd say, says that the ratio of the filling should be 20% of the weight of the dough, which just feels too little. https://youtu.be/p8hurVQxGhE?t=518. (in italian, sorry)
Last time I baked something similar, my jam was about 80% of the weight. Although it was quite of a thin layer, I found it quite balanced. A 20% layer would have been almost inexistent and the final product would have been a butter cookie with a hint of jam flavor.
Nevertheless, the baking was good and also the bottom layer got browned.
The pictures from the website of Massari's shop suggest clearly a higher ratio: https://www.iginiomassari.it/wp-content/uploads/2014/03/Crostata-confettura-d-albicocca.jpg
I'm sure that the average Italian housewife doesn't think too much about how much filling there should be, but is there an "official" value? I could google myself but I don't really trust the average Italian cooking blog; nowadays there are just too many and everybody can write all the nonsense they want in there. I'm questioning just because I heard this from Massari's own voice.