The ultimate French onion soup

Method

1. Melt the butter in a large, heavy-based saucepan that has a lid, then add the onions and bouquet garni with a generous amount of salt. Stir to coat the onions in the butter, then put the lid on and cook over a medium heat for 45 minutes to 1 hour, stirring every 5-10 minutes to make sure the onions don’t catch.
2. After this time they should be reduced in volume, very soft and a pale golden brown colour. Once they get to this stage, remove the lid 
and discard the bouquet garni. Add the garlic and cook, stirring, over a medium-high heat for a few minutes until the garlic aroma softens, then add the sugar and cook for another 10-15 minutes until the onions are a rich golden colour and taste caramelised. You need to get them right here, as once you add the wine they won’t caramelise any further. Heat the oven to 200°C/180°C fan/gas 6.
3. When the onions are well browned and caramelised, turn the heat up high and pour in the 250ml wine and 50ml brandy/cognac. Bubble briskly for 3-4 minutes to reduce the liquid, then pour in the stock and bring the soup to a gentle simmer. Cook for 10 minutes, skimming off any foam that forms on the surface, then season.
4. Meanwhile, put the baguette slices in the oven and bake for 8-10 minutes until almost completely crisp, but not too coloured. Remove and set aside, then turn the grill to its highest setting.
5. At the end of the simmering time, add the extra glug of wine and splash of brandy/cognac and taste again, seasoning if needed. Ladle the soup into heatproof bowls and top each with 2 baguette slices. Scatter over some cheese and a few thyme leaves, then put the bowls under the grill to melt the cheese.(If you don’t have heatproof bowls, transfer the soup to a large heatproof dish or pan, top with all the baguette slices and scatter over the cheese and thyme, then put the whole thing under the grill.) Serve immediately.