Lamb & shallot gravy - Good Food Middle East

Ingredients

• 2 tbsp butter
• 1 tbsp olive oil
• 4 shallots, peeled and halved
• 1 small carrot, roughly chopped
• 1 celery stick, roughly chopped
• 1½ tbsp plain flour
• 150ml dry white wine
• 2 rosemary sprigs
• 1 bay leaf
• 1l fresh lamb stock
• 2 tbsp Worcestershire sauce