French Onion Soup

Prep the onions. Peel the onions, cut them in half and then into ¼" slices.
Soften the onions. In a large pot, melt 2 tablespoons of butter and 2 tablespoon of olive oil together over medium heat. Add the onions and cook until they are soft, about 20 minutes.
Caramelize the onions. Turn the heat up to medium-high. Add 2 teaspoons of salt and stir frequently for 15 minutes. Add 1 tablespoon of sugar and continue to cook until the onions are caramelized, about 15 more minutes.
Deglaze the pot. Add 1 cup of white wine to the pot and use a spatula to scrape and deglaze the brown bits from the bottom of the pot.
Simmer. Add 8 cups of beef broth along with the 1 teaspoon black pepper, 2 bay leaves and 2 teaspoons thyme leaves. Bring the soup to a boil, turn down the heat and let it simmer for 30 minutes.
Prepare the toppings. Turn the oven broiler on HIGH. Cut the bread into slices and arrange them onto a baking sheet. Brown them under the oven broiler for 1-2 minutes. Remove the tray from the oven. Turn each bread slice over and place a slice of Swiss cheese on top. Return the baking sheet under the broiler to melt the cheese on top, 1-2 minutes.
Assemble. Ladle the soup into a bowl and place a toasted slice on top before serving.