Separate the garlic cloves, detaching them from the base; do not peel them. Blanch them for 30 seconds in a saucepan of fast boiling unsalted water; drain, refresh under running cold water and peel.

Put them in a large saucepan with 2 1/2 pints (1.4 litres) water, a large pinch of salt and some freshly ground pepper, the cloves, sage leaf, thyme, bay leaf and parsley sprigs.

Bring to the boil then simmer for 30 minutes; put through the vegetable mill with a fine-gauge sieving disc fitted; return this soup to the saucepan, add a little more salt if needed, heat to boiling point, and then turn off the heat.

Beat the egg yolks in a bowl until they are smooth and creamy; continue beating as you gradually add the olive oil a little at a time. Gradually beat in about 4 fl oz (120 ml) of the hot soup, then reverse the procedure and gradually beat the contents of the bowl into the saucepan containing the hot soup.

Make sure the liquid in the pan is no longer near boiling point. Serve with the mixed grated cheeses.