Butter both sides of the four slices of bread and make two sandwiches with two slices of ham and 75g of cheddar in each. Place the sandwiches into a frying pan and heat gently. Allow to cook for 3-4 minutes or until the cheese has begun to melt and the bread is golden. Flip the sandwiches over and cook for a further 3-4 minutes. Once the cheese has melted, remove from the pan, slice and serve immediately.