Place the gelatine leaves in a bowl of cold water and allow to soften.
Place half of the raspberry puree in a saucepan and bring to the boil. Remove from the heat.
Remove the gelatine leaves from the water and dissolve in the hot raspberry puree. Add this mixture to the rest of the puree and set aside.
Place the water, sugar and glucose in a saucepan and bring to a temperature of 121°C.
Remove the sugar syrup from the heat once this temperature has been reached and then add the raspberry puree to the pan.
Whisk the egg whites to firm peaks and then start slowly adding the raspberry mixture. Beat continually until the mixture is thick enough to hold its shape.
Spring a silicone baking sheet with a mixture of icing sugar and corn starch and then pour the marshmallow mixture on to the sheet. Dust with the icing sugar/corn starch mixture and then refrigerate for at least one hour.
Dust a kitchen knife with the sugar/starch mixture and then cut the marshmallow into cubes. Dust the cut edges with the sugar/starch mixture so that they are not too sticky. Place the marshmallows on a large sieve and gently shake off any excess sugar/starch.
«These marshmallows are best enjoyed soon after they are made but can be stored in an airtight container for up to a week.»