Family Food Fight: The Shahrouk's roast lamb with mashed potato and mushroom sauce - 9Kitchen

Ingredients

• 1kg butterflied lamb leg, trimmed
• salt and pepper
• 1 teaspoon Chinese five spice
• 100g Greek yogurt
• 65g butter
• 2 chicken supreme portions
• 1 brown onion, roots removed, skin on, chopped
• 1 carrot, peeled and cut in half
• 1 stalk celery, broken in half
• 3 bay leaves
• 1 tablespoon mixed peppercorns
• 15g flour
• 30ml olive oil
• 1 small brown onion, finely diced
• ½ small red onion, finely diced
• 3 cloves garlic, crushed
• 250g mushrooms, thinly sliced
• 1/3 cup thickened cream
• 1/2 teaspoons mustard
• pinch cracked black pepper
• pinch fine black pepper
• 1/8 teaspoon chilli flakes
• 1/8 teaspoon paprika
• sea salt flakes, to season
• 1kg potatoes, peeled roughly chopped
• 40g butter
• 2/3 cup milk