Take out the ham, and use a vegetable stock instead.
Pour the stock, cream and milk
into a small saucepan, add the
garlic and bay leaf and bring to the
boil. Remove from the heat, cover
and let the flavours infuse while you
get on with the rest of the dish.
Preheat the oven to 180C/gas
4/fan 160C. Butter a 2 litre gratin
dish well. Mix the potatoes, leeks
and ham together in the dish, and
spread out in an even layer. Pour
over the stock mixture and tuck the
bay leaf in the middle. Season and
sprinkle with the cheese.
Stand the dish on a baking tray to
catch any spills. Loosely cover with
foil and bake for 30 minutes. Test
the potatoes with a knife – they
should be just beginning to soften.
Remove the foil and bake for
another 35-45 minutes, spooning
some of the stock mixture over
every now and again until the
potatoes are tender. Cool for 15
minutes before serving.