Vegan French Onion Soup Gratinée

Caramelize Onions

1. 1Melt vegan butter in a large, heavy-bottomed pot or Dutch oven over medium heat.
2. 2Add the sliced yellow onions and cook, stirring occasionally, for 5-10 minutes until softened.
3. 3Reduce heat to low, cover the pot, and let the onions sweat for 20-30 minutes, stirring every 5-10 minutes, until very tender and translucent.
4. 4Uncover and increase heat to medium-low. Continue cooking, stirring frequently, for another 40-60 minutes, or until the onions are deeply golden brown and caramelized. Be patient, this slow caramelization is key to the flavor.
5. 5Add minced garlic and cook for 1 minute until fragrant.
6. 6Sprinkle the flour over the caramelized onions and stir to combine. Cook for 1-2 minutes to toast the flour.

Simmer Soup

1. 1Gradually whisk in the vegetable broth, scraping up any browned bits from the bottom of the pot.
2. 2Add the dry sherry or white wine (if using), thyme sprigs, and bay leaf.
3. 3Bring the soup to a simmer, then reduce heat to low, cover partially, and let it cook for at least 30 minutes, allowing the flavors to meld.
4. 4Remove thyme sprigs and bay leaf.
5. 5Season generously with salt and freshly ground black pepper to taste.

Prepare Toasts and Broil

1. 1Preheat your broiler on high.
2. 2Brush both sides of the sourdough bread slices lightly with olive oil.
3. 3Place the bread slices on a baking sheet and toast under the broiler for 1-2 minutes per side, until golden brown and crisp. Watch carefully to prevent burning.
4. 4Ladle the hot soup into oven-safe bowls.
5. 5Place one or two toasts on top of each bowl of soup.
6. 6Generously sprinkle shredded vegan gruyere cheese over the toasts.
7. 7Carefully place the bowls on a sturdy baking sheet (to catch any drips) and put under the broiler for 2-4 minutes, or until the cheese is melted, bubbly, and slightly browned. Keep a close eye on them to avoid burning.