Ingredients

2kg onions, peeled and sliced
50g butter 
15ml olive oil
1 tsp chopped fresh thyme 
1 tsp caster sugar
1 tbsp sherry vinegar 
1.5 litres good chicken stock
1½ tbs plain flour 
150 ml dry white wine
3 tbsp brandy 
Salt and ground black pepper 

Method

  1. Melt the butter with the oil in a large saucepan. 
  2. Add the onions, stir and coat them with the fat. 
  3. Cook over a medium heat for 5-8 minutes, stir once or twice, until the onions begin to soften. Stir in the thyme. 
  4. Reduce the heat to very low, cover the pan and cook for 20-30 minutes, stirring frequently, until the onions are very soft and golden yellow Uncover the pan and increase the heat slightly. 
  5. Stir in the sugar and cook for 5-10 minutes, until the onions start to brown. Add the sherry vinegar and increase the heat again, then continue cooking, stirring frequently, until the onions turn a deep golden brown. 
  6. Meanwhile, bring the stock to the boil in another saucepan. 
  7. Stir the flour into the onions and cook for 2 minutes, then gradually pour in the hot stock. 
  8. Add the wine and brandy, season to taste for 15 minutes. 
  9. Serve with cheesy croutons.