Combine 1/2 cup sprouts and whipped cream in a bowl.
Put sugar, water and coffee in saucepan and bring to a boil.
Cook, stirring, until sugar is dissolved.
Put egg yolks and rum in blender.
With motor on high speed, pour coffee mixture into blender in a steady stream.
Turn off blender and fold egg mixture into whipped cream.
Spoon parfait into individual glasses or refrigerator tray.
Sprinkle remaining sprouts on top.
Freeze several hours until firm.