French Onion Soup

1. Melt the butter with the oil in a large heavy-based pan. Add the onions and fry with the lid on for 10 mins until soft. Sprinkle in the sugar and cook for 20 mins more, stirring frequently, until caramelised. The onions should be really golden, full of flavour and soft when pinched between your fingers. Take care towards the end to ensure that they don’t burn.
   10 minutes20 minutes
2. Add the garlic for the final few mins of the onions’ cooking time, then sprinkle in the flour and stir well. Increase the heat and keep stirring as you gradually add the wine, followed by the hot stock. Cover and simmer for 15-20 mins.
   15–20 minutes
3. To serve, turn on the grill, and toast the bread. Ladle the soup into heatproof bowls. Put a slice or two of toast on top of the bowls of soup, and pile on the cheese. Grill until melted. Alternatively, you can complete the toasts under the grill, then serve them on top.

Cooking notes

Scaling works best when you weigh ingredients rather than measure by volume — small differences in packing can compound at higher multipliers.

For volume-to-weight conversions of any ingredient — flour, sugar, butter, salts — use the ingredient converter. To translate the recipe's oven temperature between °C, °F and gas mark, see the temperature converter.

When you scale this recipe up or down, remember that cooking time does not scale linearly. A doubled cake takes longer, but not twice as long; a doubled soup takes roughly twice as long. The cooking-time guide gives sensible starting estimates by dish geometry.