In a saucepan add the water, sugar and corn syrup and over medium high heat cook until it reaches 240 degrees (about 10-12 minutes).
When the egg whites are ready and the sugar reaches 240 degrees turn off the heat and wait 30 seconds.
Beat on high heat for 5-6 minutes until the bowl is no longer warm at all.
Bake for 15 minutes.
Let cool for five minutes in the fridge.
Bake an additional 15-18 minutes.
If you don't want to make your own marshmallow fluff you can substitute with one canister of pre-made marshmallow fluff. The recipe above makes 2 cups.