Warm up with this hearty Onion Soup Au Gratin recipe. Made with butter, onions, sugar and ground pepper. Easy step-by-step instructions included.
This Onion Soup Au Gratin relies on simple, everyday ingredients such as butter (4 tbsp.), to 2 tbsp. sugar, coarsely ground pepper and to 1/4 c. red wine. It comes together quickly and makes 4 servings, at about 501 kcal each. The step-by-step instructions below are written to be easy to follow, even on a busy day.
It works as a light main on its own or as a starter alongside crusty bread, and it's just as good for a cozy night in as it is for feeding a crowd. Leftovers keep well, so it's a smart choice for meal prep too.
Updated Jun 30, 2026