Peel and thinly slice the onions (about 1/4 inch thick.)
In a large, wide pan, melt the butter on medium-high heat. Add the onions and give them a good toss with the butter.
Saute for about 30 minutes, or until caramelized. Stir frequently.
Add in garlic and saute for an additional 2 minutes.
Stir in the wine. Deglaze the pan and scrape up any brown bits stuck to the bottom. Add the onions into a large soup pot.
Stir in the vegetable stock, Worcestershire sauce, bay leaves, sage, thyme, pepper, and salt.
Bring to a boil and simmer for 15 minutes. Remove the bay leaves.
In the meantime, pre-heat the oven to 400°F. Brush each slice of baguette with olive oil. Place on a baking sheet and bake for about 12 minutes, flipping halfway, or until brown and toasted.
Ladle the soup into individual oven-safe bowls. Place a toasted baguette on top and then add vegan cheese.
Broil until cheese is melty and browned, about 2-3 minutes.