Ingredients
6 tablespoon unsalted butter
1 1/2 tablespoons extra virgin olive oil
2 large yellow onions, thinly sliced
1 teaspoon sugar
6 sprigs fresh thyme
32 beef stock
1 1/2 tablespoons dry vermouth
8 slices sourdough baguette sliced into 1/2" thick pieces and lightly toasted
8 ounces shredded gruyere cheese
salt and pepper to taste
Directions
Place a large pot over medium heat and melt butter and oil together and add onions, season with salt and pepper. Cook on low heat to caramelize onions for 20 minutes, occasionally stirring.
Increase heat to medium-high, add thyme sprigs, sugar and season with salt and black pepper. Cook for an additional 15 minutes, stirring frequently.
Add stock and vermouth and bring the soup to a simmer. Simmer for about 15 minutes.
Discard the thyme stems and ladle soup into 4 oven safe bowls. Place bowls onto a baking sheet and top each soup with 2 slices of bread followed by 2 ounces shredded cheese.
Broil on high for about 1 minute, or until the cheese begins to bubble and brown. Serve immediately.