Chop the onions. Chop the celery sticks. Grate the carrots. Defrost the frozen lamb mince.
And the rest...
- 1 Heat the oil in a frying pan and cook the onion, carrot and celery for 5 minutes
- 2 Add the mince and cook until browned.
- 3 Stir in the flour, cook for 30 seconds, then add the tomato purée, thyme leaves, beef stock and Worcestershire sauce.
- 4 Season and simmer for 20 minutes, stirring occasionally, then add the petits pois.
- 5 Heat the oven to 190°C/375°F/gas 5 (170°C for fan ovens). Spoon into 4 dishes (250-300ml) or a 1.2 litre dish.
- 6 Top with the rosti, bake for 20 minutes and serve.