Preheat oven to 250° F and line a baking sheet with parchment paper or a silicone baking mat and set aside.
In a large mixing bowl, whisk together the sugars, cinnamon, and salt.
In another large mixing bowl, whisk together the egg white, vanilla, and water until frothy.
Pour the cashews into the egg white mixture and stir to evenly coat.
Pour the cashews into the sugar mixture and stir to evenly coat.
Spread the cashews evenly onto the prepared baking sheet, trying to keep them in a single layer.
Bake for 20 minutes, stir, then bake another 30 minutes.
Remove from oven and let set. Once slightly cooled, break apart any cashews that are stuck together and serve.
Video
Notes
If you like a sharp salty to sweet contrast, you can use salted cashews or increase the salt to a full teaspoon.
If you prefer, you can use all white sugar in place of the brown sugar.
Store in an airtight container for up to a week at room temperature. Longer than that, move to the fridge. If storing longer than two weeks, freeze in an airtight container for up to two months.