What we learned in Halacha class is that if it looks like bread and tastes like bread– guess what, it’s bread. If it’s eaten with a meal-like filling (tuna, cream cheese, egg, etc.) no one can get away with calling it a snack. Technically, if you take 2 slices of marble cake and eat them with tuna in between, you have to make a hamotzi. We were taught that really people should wash on pizza, because its generally eaten as a meal, whether you have 1 slice or 2, and it has a “meal-like filling” (cheese and sauce)but that’s a machlokes. Even it a person has a certain amount of, say, cake (don’t know the amount- but a lot) they even have to wash on that (even if its just for a “snack”).
As you see, this gets complicated. I suggest you ask your rabbi how he paskins.