In a skillet, melt butter on medium heat. Add all remaining ingredients (except cashews) and stir to combine well, 20 seconds.
Place cashews on large baking sheet and evenly toss them with the curry mixture until thoroughly coated. Spread cashews into a single layer. Bake 7-10 minutes or just until nuts are golden brown; take care not to let them over-bake or they'll burn.
Let nuts cool fully. They keep well in an airtight container for up to a week.