French Onion Soup

Instructions

1. 1Slice onions thinly and melt butter with olive oil in a heavy pot over medium-low.
2. 2Add onions and a big pinch of salt; cook 35–45 minutes, stirring often, until deeply mahogany.
3. 3Deglaze with sherry, scraping up the fond, and cook 1 minute to burn off the alcohol.
4. 4Pour in broth and thyme sprigs, bring to a simmer, and cook 20 minutes; taste and adjust salt and pepper.
5. 5Slice baguette and toast under the broiler until golden.
6. 6Ladle soup into oven-safe bowls, float toasts on top, and blanket with gruyère.
7. 7Broil 2–3 minutes until cheese is bubbly and starting to brown; serve immediately.