Dutch oven French onion soup

The cook

1. 01

   Step 1SORT THE FIRE

   Set up a kettle BBQ for two-zone cooking, with lit briquettes banked on one side and no fuel beneath the other. Aim for around 180°C with the BBQ lid closed. Have a 5–6 litre BBQ-safe Dutch oven ready, plus heatproof gloves and a long-handled spoon. You’ll use the edge of the direct zone to soften the onions, then gentler heat to build their colour.

2. 02

   Step 2GET THE ONIONS GOING

   Place the Dutch oven on the cooking grate at the edge of the coals. Add the butter and oil, then the onions and a good pinch of salt. Stir well and fit the pot lid. Cook for 15 minutes, stirring every 5 minutes, until the onions have softened and started releasing their liquid. You want a gentle sizzle, not an angry fry.

3. 03

   Step 3EARN THAT COLOUR

   Remove the pot lid and cook for another 45–60 minutes, stirring every few minutes and scraping the base thoroughly. Keep the BBQ lid closed between stirs. Move the pot towards the cooler zone whenever the onions catch too quickly. If brown deposits stick to the base, add a small splash of water and scrape them back into the onions. Stop when the onions are deeply golden-brown, sticky and sweet. Black bits are burnt, not extra flavour.

4. 04

   Step 4LIFT THE GOOD BITS

   Stir in the chopped garlic and cook for 1 minute. Pour the wine into a jug away from the fire, then add it to the pot. Scrape up every brown bit from the base and simmer uncovered for 5–7 minutes, until the wine has reduced by roughly half and its sharp alcoholic smell has faded.

5. 05

   Step 5LET IT BUBBLE

   Add the warm beef stock, thyme and bay leaves. Bring to a gentle simmer, then move the Dutch oven to the indirect side. Leave the pot lid slightly ajar, close the BBQ lid and cook for 30 minutes, stirring occasionally. Adjust the pot’s position if needed to keep a lazy bubble rather than a rolling boil.

6. 06

   Step 6CRUNCH TIME

   During the final 10 minutes of simmering, toast the baguette slices over the direct side for 1–2 minutes per side, watching closely. You want crisp surfaces that can stand up to the soup. Rub one side of each warm slice with the halved garlic clove. Heat your kitchen grill to high and arrange six grill-safe soup bowls on a sturdy baking tray.

7. 07

   Step 7SEASON PROPERLY

   Remove the thyme and bay leaves. Stir in the sherry vinegar, then taste before adding salt and plenty of black pepper. Stock varies wildly in saltiness, so don’t season on autopilot. Add another small splash of vinegar if the soup needs a sharper edge.

8. 08

   Step 8CHEESE, BUBBLES, JOB DONE

   Ladle the soup into the grill-safe bowls, leaving room at the top. Add two baguette slices to each and pile over the Gruyère. Grill for 3–5 minutes until the cheese bubbles and develops golden patches. Let stand for 5 minutes before serving, and warn everyone that the bowls are properly hot.