Next level cottage pie - Good Food Middle East

Ingredients

• 2 tbsp vegetable oil
• 1kg lamb mince or beef mince, or use half and half
• 2 carrots, peeled and finely chopped
• 2 onions, chopped
• 2 tbsp plain flour
• 1 bay leaf
• large pinch dried thyme
• 2 tbsp ketchup
• 2 tbsp tomato purée
• generous splash Worcestershire sauce
• 330ml dark ale
• 1.2l beef stock made with 2 stock cubes or pots
• 1½ kg King Edward potatoes or Desirée potatoes, unpeeled and kept whole
• 100ml whole milk
• 50g butter
• 2 tsp English mustard powder
• 50g extra mature cheddar, finely grated