Firstly you will need to ensure you know what you doing with the marshmallow before you do it, a few examples would be:
Making marshmallow skewers to complement other desserts
pouring into molds (ensure you use grease proof paper or a silicone mold for this)
creating bases or layers for cakes
Why this is important is because the mixture turns into marshmallows very quickly so best to understand exactly what you would like to do with it so as to have prepare for it as soon as the marshmallow is done.
0.5kg Castor sugar
0.05Kg liquid glucose
4 Egg whites
Place the water, castor sugar and liquid glucose in a saucepan and bring to the boil (you can then add a flavourant or colouring to the mixture)
Cook the sugar until it reaches 115'C, around 10 minutes if you do not have a thermometer.
In the meantime in a mixer whisk the egg whites, careful not to over beat them.
hydrate the gelatin and leave aside (it's best to use the leaf gelatin for this)
When the sugar is at desired temperature add the gelatin and make sure it is dissolved, then pour mixture into the whisking eggs and turn up the speed and beat till the mixture becomes thick and cool.
Pour the mixture onto a tray or into piping bag in order to acquire desired effect
Different flavours can be added to the sugar once you put it on the stove such as honey,cinnamon,lemon grass,ginger etc.
Try rolling the marshmallow in nuts,100's and 1000's,chocolate vermicilli, peppermint crisp, flake crumbs
To colour the marshmallows you can add liquid food colouring with the sugar mixture while boiling.
Taahir Osman Latib