French onion soup gets its full-bodied taste from slow-cooked, caramelized onions. Here, we call for three types of onions for rich, balanced flavor, but the recipe will work with any combination or just one variety. The onion mixture can be made up to two days ahead. Serve with a green salad.
1. Heat 1 Tbs. oil in saucepan over medium heat. Add sweet onion and red onion, cover, and cook 15 to 20 minutes, or until onions begin to brown.
2. Heat remaining 1 Tbs. oil in large skillet over medium heat. Add yellow onion slices, and cook 5 minutes on each side, or until browned. Transfer to paper-towel-lined plate. Set aside 12 prettiest yellow onion slices, and chop remaining yellow onions.
3. Add chopped yellow onions to sweet and red onions. Cook, uncovered, 5 minutes, or until all onions are browned. Add wine, and cook 1 to 2 minutes, or until most liquid has evaporated. Stir in broth, honey, and thyme; season with salt and pepper, if desired. Partially cover, and simmer 10 to 20 minutes, or until most liquid has evaporated.
4. Preheat oven to broil. Place bread slices on baking sheet. Spread 1/4 cup cooked onion mixture on each slice of bread. Top with grated cheese. Lay 3 reserved sautéed onion slices on top of each tartine. Broil 2 to 3 minutes, or until cheese begins to bubble and brown.