Drain the juice from the can of cherries into a bowl, add the gelatine leaves and leave to soak until they are soft (about 10 minutes).
Meanwhile, put the egg whites into a separate bowl and whisk with an electric mixer on medium speed until the mix holds a ribbon trail when the mixer is lifted.
At the same time, put the sugar, water and glucose into a saucepan over a medium heat and heat to 127C on a sugar thermometer.
Add the cherry juice and gelatine to the pan of sugar syrup on the heat and stir carefully until the gelatine has dissolved.
This should only take about a minute.
Slowly pour the hot sugar mixture on to the egg whites and continue whisking until all of the sugar has been absorbed.
Continue whisking for a further 5-8 minutes until it looks like a tight, sticky meringue.
Allow the meringue to cool slightly in the bowl, then stir in the poppy seeds and pour the mixture into the greased tray.
Leave to set in the fridge for 3 hours or until firm.
Sprinkle the mallow dust over a board.
Turn the marshmallow out on to the dust and turn to coat, then cut into sixty 2cm cubes.
Eat, toast or mix into a knickerbocker glory.
They only keep for a couple of days, so eat loads quickly!