Heat the 4 tablespoon butter and 2 tablespoon olive oil in a stock pot over medium-high heat.
When the butter is melted and beginning to bubble, add the onions and stir to coat in the butter and oil.
Stir the onions often, and once they soften (approximately 5 minutes), reduce the temperature to medium-low heat and continue to stir until they lightly caramelize, approximately 10 to 15 minutes. They should be a light golden color.
Add the 1 cup of wine or 1 tablespoon of balsamic vinegar to the onions and stir to coat. Cook for approximately 5 minutes, or until the liquid is reduced.
Add the 2 tablespoon flour and stir to coat the onions. Cook for one minute.
Add the garlic and cook for one more minute.
Pour in the 64 oz of vegetable broth, 2 teaspoon dried thyme, 2 bay leaves, and salt and pepper to taste. Bring to a boil and then reduce the heat to a simmer for 15 minutes.
Fill 6 to 8 bowls with the soup and then place one slice of toasted bread on top of the soup and sprinkle a liberal amount of the vegan mozzarella on top of the bread and broil until the cheese is melted and browned on the edges. Keep your eyes on it the ENTIRE time it’s under the broiler so it doesn’t burn.