Remove the skin (leaving fat) from a whole or half leg ham.
Using a small, sharp knife, score the fat in diamond shapes, then place a clove in the centre of each diamond.
Preheat the oven to 160°C. Combine paste, lemon juice and 100ml water in a saucepan over low heat. Cook, stirring, for 5 minutes until paste dissolves and liquid is smooth. Add butter and stir to melt. Cool slightly. Brush ham with the glaze.
Place on a rack over a large roasting pan, and half-fill the pan with hot water. Carefully place in the lowest part of the oven and bake for 40 minutes, basting 3-4 times until all the glaze is used. Serve either hot or cold.
