Preheat oven to 300F
Combine brown sugar, salt, cayenne, and cinnamon in a large bowl. Set aside.
In a medium bowl, combine the foamy egg white and water and toss the nuts in this mixture to coat.
Next, dump the egg-coated nuts into the sugar and spice mixture. Toss to coat thoroughly and as evenly as possible.
Line a baking sheet with parchment and spread the coated nuts evenly across the pan.
Bake at 300F until the nuts are crispy and toasted, about 30-35 minutes.
As soon as they come out of the oven, pour the melted bacon grease over the top, taking care to pour in a thin stream and coat the nuts lightly but evenly on their tops.
Allow nuts to cool completely, then break them apart and allow them to dry completely. Enjoy immediately, pack into gift jars, or save for up to 3 weeks for a fine party snack.