140g granulated sugar
70g glucose syrup
4 egg whites
1 pinch of salt
1 teaspoon vanilla essence
1 cup of mixed icing sugar and corn starch, in equal parts
Butter for greasing
Grease a rectangular baking tray and sprinkle it with the mix of icing sugar and starch.
Soak the gelatine in cold water.
Put the glucose syrup, sugar and 55ml of water in a saucepan and heat on a medium heat. Leave a thermometer immersed in the syrup.
When the temperature approaches 100°C, start whipping the egg whites with the salt until you get a firm consistency.
When the syrup reaches 118°C (it will take a while, have faith and do not lose sight of the thermometer!), pour into the egg whites down the side of the bowl whilst whipping constantly.
Add the gelatine and a few tbsp of water to the warm pan and stir to dissolve. Add too the egg white/syrup mix whilst whisking on a high speed. Add the vanilla.
Keep whisking until the bowl that contains the mixture has returned to room temperature, otherwise the bottom of your marshmallows will be wet.
Pour the mixture into the tray and let it rest overnight in a cool, dry place.
Sprinkle the surface of the marshmallow slab with the sugar and starch mix, as well as the knife you will use to cut the marshmallows into cubes.
Marshmallows keep for a week at room temperature in a closed box.