Bring the stock to the boil in a large saucepan, then gradually
stir in the polenta.
continue stirring the polenta over moderate heat for about 5
minutes, until the mixture begins to come away from the sides of the
pan.
Stir in the chopped sage and season well, then spoon the polenta
into a lightly oiled, shallow 23 x 33 cm tin and spread evenly.
Leave to cool.
Preheat the oven to 200oC/400oF/Gas 6.
Cut the cooled polenta into 24 squares using a sharp knife.
Arrange the polenta overlapping with tomato slices in a lightly
oiled, shallow ovenproof dish.
Sprinkle with Parmesan and bake for 20 minutes, or until golden
brown.
Serve hot.
Serves 4
To make a more substantial meal, omit the Parmesan cheese and arrange
slices of mozzarella cheese in between the tomato and polenta slices
before baking.