Shepherd's pie with cheesy mash | Kerrygold Australia

Ingredients

• 2 tbsp olive oil
• 2 onions, finely diced
• 2 celery sticks, finely diced
• 2 carrots, finely diced
• 1 tsp soft fresh thyme leaves
• 450g (1lb) lean minced lamb
• 2 tsp plain flour
• 1 tsp tomato purée
• 1 tsp strong English or Dijon mustard
• 1 tbsp (¾ pint) (2 cups) lamb or chicken stock (from a stock cube is fine)
• For the cheesy mash
• 1kg (2 ¼lb) potatoes, cut in chunks
• 25g (1 oz) (2 tbsp) Kerrygold Pure Irish Salted Butter
• 4 tbsp milk
• 75g (3 oz) (¾ cup), grated Kerrygold Light Cheese
• Salt and freshly ground black pepper
• Buttered peas, to serve