Melt the butter in a Dutch oven or large soup kettle over medium heat. Add in the onions, salt, bay leaf, and the sprigs of thyme and cook the onions until caramelized (~30-45 minutes), stirring frequently.

When caramelized, remove the bay leaf and sprigs of thyme. Add in the garlic and cook until aromatic (~30 seconds)

Optional step to thicken your soup: stir in flour to coat onions, allowing to thicken for 1-2 mins

Add wine and scrape the bottom of the pan with a wooden spoon to deglaze. Add bone broth and simmer for 10 minutes

Add additional salt and pepper to taste prior to spooning into crocks

Heat your oven’s broiler. Spoon soup into crocks or oven-safe bowls. Top each bowl with 2-3 slices of bread and a generous amount of cheese. Broil to melt cheese (watch your soup closely!) and serve immediately