In a large pot, melt down the butter with the olive oil. Add the sliced onions, along with some salt, and sauté on medium-low heat for about 20 minutes until golden brown and caramelized. Optional: add in some minced garlic when the onions are almost done caramelizing.

Deglaze with the white wine, stirring to scrape up all the browned bits.

Add the bone broth, miso paste, a few sprigs of fresh thyme, and a bay leaf. Simmer for 15 minutes.

Remove the herbs and then ladle the soup into oven safe bowls or crocks.

Toast up some sourdough, then brush lightly with olive oil. Top each bowl with a piece of the toasted bread and plenty of grated cheese.

Place the soups under the broiler until golden and bubbly. Garnish with some extra fresh thyme!