Cut the porcini mushrooms, sauté briefly in a mixture of butter, salt and pepper. Prepare mayonnaise from mustard, egg yolk, chestnut honey and hazelnut oil: first blend mustard and honey with the egg yolk and then slowly pour in the hazelnut oil, stirring constantly. Poach the second yolk and drizzle with hazelnut oil. Serve by first placing the mayonnaise on a plate, adding poured porcini mushrooms to it and top it off with a poached egg yolk. Garnish with shiso or lettuce leaves.