Classic Shepherd's Pie - The Australian Made Campaign

Ingredients

• 1 tablespoon olive oil
• 1 brown onion, halved, finely chopped
• 1 carrot, peeled, finely chopped
• 2 celery sticks, trimmed, finely chopped
• 1 tablespoon tomato paste
• 500g lamb mince
• Salt & freshly ground black pepper
• 2 tablespoons plain flour
• 500ml (2 cups) beef style stock
• 1 tablespoon Worcestershire sauce
• 1 bay leaf
• 4 (about 200g each) desiree potatoes, peeled, chopped
• 40g butter
• 125ml (1/2 cup) milk
• Melted butter, to brush