Place water, sugar, and corn syrup in a medium saucepan over medium-high heat. Stir to combine. Then let saucepan sit on heat (without stirring) until the mixture reaches 240°F on a candy thermometer (this will likely take about 10-15 minutes).
While mixture is heating, place egg whites in the bowl of a stand mixer fitted with whisk attachment. Beat on medium until egg whites are foamy. Add cream of tartar and salt and increase mixer speed to high, continuing to beat until soft peaks form (this means egg white will droop a bit when you lift out the beater).
Once syrup comes to temperature, turn the mixer back on low and very slowly pour the syrup into the egg whites. Once all syrup is poured, increase speed to high and mix for 5-6 minutes, until mixture fluffs up and is glossy.
Add vanilla and crushed freeze-dried strawberries and mix on high for another minute.
Store strawberry fluff in an airtight container and keep in the fridge. It should stay fresh for about 2 weeks.