Ohhh, we call it a Napoleon as well. The French bakeries will call it Mille-feuille. Ditto on being a favorite ( back in the days when I ate gluten) and I too never made one. I have a number of recipes, but every time I make puff pastry I end up using it for something else.Welcome to the forum @melani!
@Norcalbaker59 here in the UK a vanilla slice is what you'd call a Napoleon (also known as mille-feuille). I'm guessing that's what Melani is referring to. They are one of my favourite things, although I've never baked them myself. I'm very good at eating them though