Welsh Lamb rarebit hotpot

1. Heat the oil in a frying pan. Lightly fry the leek and onion until coloured.
2. Add the lamb and stock. Heat through until piping hot. Transfer the mixture to an over proof dish.
3. Overlap the sliced potatoes around the edge of the dish.

To make the rarebit:

1. Combine the cheese, mustard and ale to a thick paste.
2. Spread the paste over the potatoes. Place under a hot grill for 10 minutes, until golden brown.