French onion soup

Ingredients

• 50g Butter
• 1 tbsp Olive oil
• 1kg Onions halved and thinly sliced
• 1 tsp Sugar
• 4 Garlic cloves thinly sliced
• 2 tbsp Plain flour
• 250ml Dry white wine
• 1.3l Hot strongly-flavoured beef stock
• 4-8 slices Baguette (depending on size)
• 140g Gruyère finely grated