In a large stainless-steel skillet, combine cashews, sugar, and 1/4 cup water. Bring water to a boil over high heat. Lower heat and simmer, stirring frequently, until water evaporates and sugar crystallizes around nuts, about 5 minutes.
In a small bowl, combine coriander, cinnamon, allspice, cayenne, and coarse salt. Stir into nuts and continue cooking, stirring constantly, until sugar begins to melt and caramelize, 1-2 minutes.
Remove to a parchment-lined baking sheet and cool to room temperature before serving, about 5 minutes.