Scrape vanilla beans, add to milk and heat. Whisk yolks and sugar very gently. Add hot milk and temper yolks; cool. Add heavy cream. Pass through fine chinois. Skim foam and pour into molds. Cook in a bain-marie system, covered, at 300 degrees 45 to 50 minutes. Chill thoroughly. Sprinkle tops with sifted Demerara sugar and glaze under salamander.
Serves 8.