Tightly wrap each ramekin with a 4 cm (approximately 1 1/2 inches) high piece of baking paper, making ramekin taller, and secure with a rubber band.
For the parfait, rinse strawberries, trim and pat dry.
Place 300 grams (approximately 10 1/2 ounces) in a mixing bowl and puree with an immersion blender. Pass through a fine sieve and mix with mascarpone into a smooth cream. Stir in liqueur. Cut remaining strawberries into small pieces.
Separate eggs. Place yolks in a metal bowl and beat over a hot water bath with sugar and vanilla sugar until a frothy cream forms. Place in an ice-water bathto cool, stirring occassionally.
Fold egg yolk mixture into strawberry puree and stir. Beat egg whites and heavy cream until stiff and fold gently into strawberry mixture. Fold in strawberry pieces. Pour mixture into ramekins and freeze for at least 3 hours.
Approximately 30 minutes before serving, place ramekins in refrigator to thaw slightly. To serve, remove paper borders.