Ingredients
- 4 tbsp. butter
- 1 tsp salt
- 4 large thinly sliced yellow onions
- 48 ounces chicken broth
- 14 ounces beef broth
- 1/2 cup red wine
- 1 tbsp. worchestershire sauce
- 1 sprig fresh thyme leaves
- 1 bay leaf
- 1 tbsp balsamic vinegar
- 1/4 cup medium dry sherry
- Salt and freshly ground black pepper
- 4 thick slices french bread
- 8 slices gruyere cheese
- 1/2 cup shredded asiago cheese
Preparation
Step 1
In a large pot, melt butter. Add onions and salt- cook 35 minutes, stirring frequently, until onions are caramelized and almost syrupy.
Mix chicken broth, beef broth, red wine, sherry and worcestershire sauce into pot. Add whole thyme stem and bay leaf. Simmer over medium heat for 20 minutes, stirring occasionally. Remove and discard the thyme stem and bay leaf. Reduce the heat to low, mix in vinegar and season with salt and pepper. Cover and keep over low heat to stay hot while you prepare the bread
Preheat oven broiler. Arrange bread slices on a baking sheet and broil 3 minutes, turning once until well toasted on both sides. Remove from heat, do not turn off broiler.
Arrange 4 large oven safe bowls on a baking sheet. Fill each bowl 2/3 full with hot soup. Top each bowl with 1 slice toasted bread, 2 slices gruyere cheese and 1/4 of asiago.
Broil 5 minutes, or until bubbly and golden brown. Serve immediately