Preheat oven to 325 degrees and line a baking sheet with parchment paper, set aside.
In a medium mixing bowl add white sugar, cinnamon, pumpkin spice (optional) and sea salt and stir to combine.
In a large mixing bowl whisk together egg white, vanilla and water until it becomes foamy. Add in the walnuts, almonds and cashews and toss to combine, making sure to evenly coat all of the nuts. Top the nuts with the sugar mixture, stirring evenly to coat.
Add nuts to prepared baking sheet in a single layer and bake for 10 minutes. Stir nuts mixture and bake for another 10 minutes. Stir nuts mixture again and bake for another 10 minutes. Stir nuts once more and bake for another 5 minutes. Remove nuts from oven and allow to cool completely.
Use for a salad topping, as cold cereal, a sundae topping, a side to your meat and cheese tray, or package them up for a holiday gift!