Preheat the oven to 400 degrees F. and have ready a large, rimmed baking sheet.
In a large saucepan, bring about 2 cups of water to a boil. Add the nuts and boil the nuts for 2 minutes (this removes some of their bitterness). Drain well. If you are using roasted salted cashews, you do not need to boil.
In a large skillet, melt the butter.
Mix together the ginger, cumin, salt, cayenne and granulated sugar and add to the butter. Add the soy sauce.
Add the nuts and toss until nuts are warm and coated with the spice mixture.
Spread nuts on a baking sheet and bake for about 8 to 10 minutes or until they are lightly toasted. Let cool and crisp. If they're not spicy enough for you, sprinkle with red pepper flakes.
Notes
For the cashew version, use the same amount of roasted and lightly salted cashews, but omit the salt from the spice mixture. Since the cashews are already roasted, you'll only need to bake them for about 8 minutes at 350F or just until they brown. For extra heat, sprinkle with red pepper flakes. You may want to add a pinch or two of extra sea salt was well. Raw cashews might also work, but I only tested with roasted & salted. The original recipe is from one of my favorite places in CT, Stew Leonard's