A hearty meal for four in one pot. Tender lamb cooked in a richly flavoured casserole with crisp layered potatoes on top.
Each serving provides 455 kcal, 31g protein, 47g carbohydrate (of which 13g sugars), 14g fat (of which 5g saturates), 10g fibre and 1.7g salt.
Preheat the oven to 160C/140C Fan/Gas 3.
Heat 1 teaspoon of the oil in a large heavy-bottomed casserole over a medium to high heat. Brown the lamb on all sides in two batches for 3-4 minutes per batch. Transfer to a plate using a slotted spoon.
Add another teaspoon of oil to the pan and add the onions, garlic, celery and carrots and fry, stirring, for 3-4 minutes. Add the rosemary and thyme and fry for another minute. Sprinkle over the flour and cook for 2 minutes, stirring all the time to cook the flour.
Return the lamb to the pan, pour in the stock and stir in the Worcestershire sauce and tomato purée, then bring to the boil.
Layer the potatoes on top in two overlapping layers, seasoning between the layers. Cover with the lid and bake in the oven for 1½ hours, or until the lamb and the potatoes are tender.
Remove the lid and increase the oven temperature to 200C/180C Fan/Gas 6. Brush the potatoes with the final teaspoon of oil and bake for a further 15 minutes, or until the top is nicely browned.