…baked goods where the primary solid ingredient is flour from one of the 5 species of grain should be hamotzi on matter what amount eaten…
… whatever bread you are referring to, is probably Hamotzi according to Ashkenazim, even if you eat one crumb at 3 AM…
If so, please explain why melba toast or soup/salad croutons made of very small pieces of actual bread are mezonos?
I know that eating less than a kzayis of bread does not need a brocha of al netilas yadayim when washing nor birchas hamazon after it. But it is still hamotzi, whereas melba toast or bread croutons are mezonos. Why?