Bring a small pot with a little water to a boil.
Cut the vanilla bean lengthwise and scrape out the pulp.
Beat eggs, yolks, vanilla pulp and sugar in a snow kettle over steam with a mixer until very foamy, occasionally lifting the kettle so that the steam can escape and the eggs do not get too hot. The mixture is then optimal when you blow on a spoon some of it in the middle and the wave formation is maintained and does not run together again liquid (that is “pull off to the rose”).
Beat the egg foam in a cold water bath with a mixer until cold, whip the whipped cream until creamy, but not spoon-firm, and fold into the egg mixture. Coarsely crumble the vanilla crescents and stir them in as well, and possibly the Cointreau.
Line any mold with plastic wrap, pour in mixture and freeze in freezer for at least 6 hours, preferably overnight.
Cut couverture into small pieces, melt in a bowl in a bain-marie or in the oven, stirring occasionally and do not heat to more than 45 °C (otherwise it will become dull and dull). Squirt liquid couverture in a paper piping bag or with a spoon in a thin stream in a pleasing criss-cross pattern on a baking paper or drizzle on targeted figures. Allow to cool.
Turn out the parfait from the molds. To do this, hold the mold briefly under lukewarm water and loosen from the edge with a small knife. Garnish the vanilla crescent parfait with Amarena cherries and chocolate ornaments.