Ingredients for 4 people
Heat the cream and milk to a temperature of 80°C, stir in the grated Pecorino Romano and mix well. Pour into a soda-water siphon and keep warm. Peel the potatoes and cut into small cubes. Cook them in a few drops of oil together with a clove of garlic and the bay leaf, soak with a little broth or water, bring to the boil, take out the garlic and bay leaf and blend until the mixture is smooth and creamy. In a small saucepan, boil some water with a pinch of salt and a drop of white vinegar. Break open the egg and drop carefully into the boiling water; cook for 3 minutes until it is properly poached.
Drain and lay it onto a sheet of absorbent paper. In a soup dish place a spoonful of the creamed potatoes, spray on some of the Pecorino foam using the siphon, place the egg in the center and garnish with bread croutons and a few drops of must.
Serve piping hot with a dash of freshly-ground pepper over the egg.