Weigh the gelatine and add the cold water to obtain total weigh of 85g.
Cook the inverted sugar with the 300g of caster sugar and the 70g of the strawberry pulp at 110 C. Pour the cooked sugar syrup into a mixing bowl over the inverted sugar and the remaining 70g of strawberry pulp.
Melt the gelatine in a microwave then pour over the hot sugars and beat until the mixture reaches the ribbon stage. When the marshmallow has cooled and is still slightly runny, incorporate the colouring, then as soon as the mixture has reached 35/40 C, pour into 10cm tray, placed with a buttered silicone sheet. Smooth with a palette knife.
Allow to gel for 30 minutes, and then sprinkle the surface with a mixture of icing sugar and some corn starch. After the marshmallow has gelled for several hours, cut into 10 by 10cm cubes with knife.
Immediately roll the cubes in a glass jar with the mixture of icing sugar and corn flour.