Side

Melt butter and olive oil in a large heavy-based pan
Add onions, cover, and fry 10 minutes until soft
Add sugar and cook 20 minutes, stirring frequently, until caramelised
Add garlic for the final few minutes of cooking
Add flour and stir well
Increase heat and stir while gradually adding the wine, then add hot stock
Cover and simmer 15-20 minutes
Turn on the grill and toast the bread
Ladle soup into heatproof bowls
Place a slice or two of toast on each bowl and pile on the cheese
Grill until the cheese has melted