My uncle used to make this rich savory bake every Sunday and I finally stole his secret. Takes just 4 ingredients for absolute perfection and the crunch is unreal.

To keep this true to the 4-ingredient spirit, most of the flavor comes from the soup, cheese, and fried onions, but you can still customize it subtly. For a slightly sharper profile, swap half of the provolone for Swiss or Gruyère slices; they melt beautifully and lean into the classic French onion soup flavor. If you prefer darker, beefier notes, choose a condensed French onion soup that lists beef stock high in the ingredients, or add a splash