oven-baked french onion soup with gruyere toasts

serves 4, hands-on time 30 min, oven time 2 ½ hours

Make the soup up to the end of step 1. Cool, then keep in a sealed container in the fridge for 3-4 days, or in the freezer for up to 2 months. Reheat until piping hot and continue with step 2.

6 medium onions, thickly sliced
6 garlic cloves, halved
2 tbsp balsamic vinegar
2 tbsp caster sugar
Small bunch fresh thyme
100g unsalted butter
1 litre fresh beef stock
300ml fino sherry, such as Tio Pepe
1 baguette or sourdough loaf, sliced
200g gruyere, grated

Heat the oven to 160°C/140°C fan/ gas 3. Divide the onions and garlic equally between 2 medium roasting tins (about 2.5 litres capacity each). Add 1 tbsp vinegar, 1 tbsp sugar, half the thyme and 50g butter to each tin, then divide the stock and sherry equally between the tins, too.

Cover both tins with a layer of baking paper, then a layer of foil, transfer to the oven and cook for 2 ½  hours. At the end of the cooking time, transfer the contents of both tins to a heatproof ceramic 2 litre dish.

Set the grill to high. Place the bread slices on top of the onion soup, then top with the cheese.
Put under the hot grill for 5 minutes or until the cheese has melted and turned golden. Serve straightaway.

PER SERVING 883 kcals, 39.6g fat (24g saturated), 29.2g protein, 77.6g carbs (28.5g sugars), 3.3g salt, 8.5g fibre