Method

1. Put the jam in a food processor and blitz until smooth.
2. Fill a saucepan with 180ml of water and place the gelatine sheets in it, pushing them down into the water until fully covered. Leave to soften for 10 mins.
3. Line a 20cm x 30 cm x 3cm tin with clingfilm and brush with oil. Put the pan with the water and gelatin over a low heat until the gelatin has dissolved. Set aside to cool slightly.
4. In a separate pan, combine the sugar, 125g glucose and 3 tbsp water. Bring to the boil, stirring occasionally, and heat until the mixture reaches 112ºC on the thermometer. Pour into a large mixing bowl.
5. Quickly add the remaining glucose to the bowl and begin whisking on a low speed.
6. Add the cooled gelatin and its liquid, the jam and the food colouring. Increase the speed to medium and whisk until thickened. Continue to whisk, turning the speed up to high, for a further 10-12 mins or until the mixture is thick and marshmallow-like in consistency.
7. Transfer the mixture to the prepared tin and cover with clingfilm. Leave to set at room temperature for a minimum of 4 hours.
8. To make the coating, put the sugar and freeze-dried raspberries in a food processor and blitz until the raspberries have broken down to a fine powder and are well incorporated with the sugar. With the motor still running, add the food colouring, adding a drop at a time until you reach your desired shade.
9. Pour the sugar into a shallow dish. Remove the marshmallow from the tin and transfer to a chopping board. Cut the marshmallow into cubes and then toss one by one in the coloured sugar until well coated.