Attempting to make a vegetarian French onion soup is a challenge because most versions rely on beef broth. Red wine, tomato paste, and fresh herbs flavor this soup. Don't be tempted to use sweet yellow onions - besides being too sweet, they're also watery.
2 teaspoons butter
4 red onions, quartered and thinly sliced crosswise (about 2 1/2 pounds)
1 teaspoon sea salt
1/4 teaspoon freshly ground black pepper
1 cup dry red wine
2 tablespoons tomato paste
1 quart water
1 cup canned diced tomatoes, drained
1 teaspoon minced fresh rosemary
1/8 teaspoon dried thyme
4 parsley sprigs
2 bay leaves
1 tablespoon low-sodium soy sauce
6 (1/2-inch-thick) slices diagonally cut French bread baguette
3/4 cup (3 ounces) shredded Gruyère cheese
1/3 cup (1 1/2 ounces) grated Asiago cheese
How to Make It
Melt the butter in a large Dutch oven coated with cooking spray over medium heat. Add the onions, salt, and pepper; cover and cook over low heat 30 minutes or until onions are browned, stirring occasionally.
Increase heat to medium-high; stir in wine and tomato paste. Cook until wine almost evaporates (about 5 minutes). Add water, tomatoes, rosemary, thyme, parsley, and bay leaves; bring to a boil. Cover, reduce heat, and simmer 20 minutes. Stir in soy sauce; discard parsley and bay leaves.
Ladle 1 1/3 cups soup into 6 ovenproof bowls. Place bowls on a baking sheet. Top each serving with 1 bread slice, and sprinkle each bread slice with 2 tablespoons Gruyère and about 1 tablespoon Asiago. Broil 3 minutes or until cheese melts.