Make the onions overnight. They don’t need tending.
Follow the recipe through Step 5 for Caramelized Onions. Store them in the refrigerator for up to 3 days or freeze to use later. (Be sure to thaw frozen onions if proceeding to make soup.)
Make It Gluten-free: Use gluten-free bread or croutons.
Make It Vegetarian/Vegan: Substitute vegetable broth, preferably one with mushrooms, for the beef broth. Use a vegan cheese and sprinkle nutritional yeast on the bread.
Simple Swaps: Substitute leeks for half the onions. Switch up the toppings with different types of cheese.