Ingredients:
- 1.5 kg yellow onions, thinly sliced
- 50g unsalted butter
- 4 sprigs fresh thyme
- 120ml dry sherry
- 800g canned butter beans, drained with 60ml liquid reserved
- 1.2 liters beef stock
- 1 tbsp Worcestershire sauce
- 8 thick slices sourdough baguette
- 200g Gruyère cheese, grated
- 1 clove garlic, peeled
Instructions:
- Slice the 1.5 kg of yellow onions into thin, even half moons. Uniformity ensures they all finish caramelizing at the same time.
- Melt 50g unsalted butter in your heavy pot over medium low heat.
- Add onions and 4 sprigs of thyme, stirring to coat them in the butter.
- Cook for 35-40 minutes, stirring every few minutes, until onions are deep mahogany and jam like. If they stick too much, add a splash of water to loosen the browned bits.
- Pour in 120ml dry sherry to deglaze. Cook for 2 minutes until the liquid has mostly evaporated.
- Add 1.2 liters beef stock, 1 tbsp Worcestershire sauce, and the 800g butter beans (plus 60ml reserved liquid).
- Simmer for 15 minutes to let the flavors marry. Remove thyme sprigs before serving.
- Toast the 8 sourdough slices under the broiler until golden and shatter crisp.
- Rub the toasted bread with the halved garlic clove.
- Ladle soup into bowls, top with bread and 200g grated Gruyère, then broil for 2-3 minutes until bubbling and browned.