Boil the water and very slowly, mixing all the time, pour in polenta until it thickens and stirring becomes tough. Then stop pouring in polenta, let it cook until it is smooth to the taste, stirring all the while. Instant polenta will be quicker than the classic polenta.
Remove and immediately pour onto a big chopping board.
Smooth it out as much as possible to an even thickness – about ¾ inch/2cm.
Using a small glass, cut out rounds and oil them lightly.
Put them onto a hot grill and leave until grill marks appear. Do both sides.
Slather on a little pesto and top with a small piece of ham, a ¼ of a slice of tomato and ½ a tiny bocconcini mozzarella.
Place under the grill for about 5 minutes until the cheese is melted.
Serve with a lovely cold glass of wine.