Onions, red, white, sweet mix; halved and thinly sliced lengthwise | 16 cups |
Oil, extra-virgin olive | 2 tablespoons |
Butter, unsalted | 2 tablespoons |
Sherry, oloroso | ¼ cup |
Vegetable or chicken stock, low-sodium | 6 cups |
Thyme, fresh | 6 sprigs |
Salt, kosher | 1 tablespoon + |
Pepper, freshly ground | 1 teaspoon + |
Vinegar, sherry or white balsamic | 2 teaspoons |
Bread, day old, cut in chucks to cover soup bowl | 6 slices |
Cheese, blue cheese, chilled, thinly sliced or crumbled | 6 ounces |
- In a stockpot over medium-high heat, toss together the onions, oil, and butter.
- Cook, stirring occasionally, until the onions start to caramelized, about 20 minutes.
- Reduce heat to medium, and continue to cook, stirring and scrapping the bottom any browned bits from the bottom of the pot, until the onions are tender and caramelized, about 30 minutes.
- Add sherry and cook, scrapping up browned bits from the bottom of the pot.
- Simmer over medium, stirring occasionally, until the sherry is almost evaporated, 2 to 3 minutes.
- Stir in the broth, thyme, salt, and pepper.
- Increase heat to high, and bring to a boil.
- Reduce heat to medium-low, and simmer, partially covered, until flavors marry, 20 to 25 minutes.
- Stir in vinegar and cook 1 minute; adjust salt and pepper to taste.
- Preheat oven to broil with an oven rack 6 inches from heat.
- Remove and discard the thyme sprigs.
- Divide hot soup evenly among six ovenproof crocks or bowls, and place on a rimmed baking sheet.
- Place bread pieces on each bowl, and gently push them down until half-submerged but still at top of soup.
- Add cheese to each bowl.
- Broil until cheese is melted, bubbly, and browned in spots, 2 to 3 minutes.