For the mini foam rolls, whisk the cold QimiQ vanilla until smooth and add rum as desired. Mix together the powdered sugar, vanilla sugar and cream stiffener.
Whip the cream for 1/2 minute, then add the mixed powdered sugar and whip until stiff. Carefully fold the stiff whipped cream into the QimiQ mixture and chill slightly.
Meanwhile, roll out the puff pastry and cut 8 mm thin strips. Roll the puff pastry strips onto small foam roll molds (6.7 cm long, approx. 1.2 to 1.6 cm in diameter), leaving the top and bottom ends 1.5 cm free.
Bake at about 170 degrees convection until light brown and remove from the molds while still hot. Allow the foam rolls to cool, then pour the cooled QimiQ mixture into a piping bag and fill the foam rolls with it.
Chill the mini meringue rolls for a few hours and then sprinkle with powdered sugar.