A thick and rich soup made with caramelized onions in beef broth and topped with a French baguette slice and Gruyere cheese.
Melt butter in large Dutch oven or large pot over medium-high heat. Add sliced onions and 1/2 teaspoon salt, stirring to coat onions thoroughly with butter. Cook, stirring frequently, until onions are reduce and caramelized, approximately 30 minutes.
Stir in the broth, wine, parsley, thyme, and bay leaf, deglazing the bottom on the pot with a wooden spoon to loosen browned bits. Bring to a simmer and continue to simmer for 30 minutes.
Stir in the balsamic vinegar and salt and pepper to taste.
When ready to serve adjust the oven rack to upper middle position; heat the broiler.
Using fairly deep, oven- and broiler-safe serving bowls/crocks, place on a baking sheet and fill 3/4 full with the soup. Then top each bowl with toasted bread slices - covering the entire surface of the soup, but do not overlap the bread. Divide cheese slices, laying them in a single layer on top of the bread, overlapping the edge of the dish. Make sure to cover the entire dish with cheese.
Place the bowls into the oven, about 5 to 6 inches from the broiler and broil until cheese is bubbly and begins to turn brown, approximately 8-10 minutes.
Recipe courtesy of Old World Garden Farms