This is a very useful concoction if you are expecting a lot of people for dinner. It looks and tastes splendid, but the great thing is you can prepare it the day before, then just bung it in the oven when required.
Soak the gammon for 12 hours, changing the water a few times. Place in a snug saucepan and cover completely with cold water. Bring slowly to simmering point and cook at a bare tremble for half an hour to each
Slice the washed and trimmed leeks finely, using the slicing device of a food processor or with a good, sharp knife. Melt the butter in a large saucepan and stew the leeks until tender. Add the flour and stir until well mixed with the leeks. Add the warm milk, little by little, together with the warm vermouth, stirring all the time to make a smooth sauce. Season with a generous amount of freshly ground black pepper and very little salt. Simmer very gently for 20—30 minutes, stirring occasionally. Use a heatproof mat if available. Add the cream and the cheese, mixing well until the cheese has melted. Check the seasoning, remembering the ham will be salty.
Carve the ham into thickish slices. Pour half the sauce into a good earthenware oven dish. Arrange the ham in overlapping slices on the sauce, then cover with the remaining sauce. Dot with tiny bits of butter and heat in a hot oven for 10 minutes. Finish off under the grill until the top is brown and bubbly.
Serve with some simple new potatoes and something bright green, like spinach or broccoli. This is also a good way to use leftover ham, with half or a quarter of the amount of sauce.
© 1996 Jennifer Paterson and Clarissa Dickson Wright estate. All rights reserved.