Prepare the onions

• Slice the end off each onion and peel them.
• Slice the onions thinly.
• Put the sliced onions into a large pot.

Start cooking the onions

• Add the olive oil and butter to the pot.
• Season with salt, pepper and a little sugar.
• Start cooking the onions down.

Caramelize low and slow

• Cook the onions over low heat, stirring occasionally, until soft and deeply golden.
• Meanwhile, smash and dice the garlic.

Deglaze and add garlic

• Pour in the sherry and the Worcestershire sauce.
• Add the diced garlic and a little garlic oil.
• Stir and let the alcohol cook off.

Toast the baguette

• Slice the baguette into pieces and drizzle with garlic oil.
• Toast in the oven until golden and crisp.

Simmer the soup

• Add half of the beef broth along with the rosemary and thyme.
• Let it simmer a little, then add the remaining beef broth.
• Simmer gently, partly covered.

Assemble and broil

• Ladle the soup into ovenproof bowls.
• Top with the toasted baguette pieces and plenty of grated Gruyère.
• Broil until the cheese is melted and bubbling.