Preheat oven to 350 degrees F. Line a 15x10x1-inch baking pan with parchment paper or foil. Spread cashews in an even layer in the prepared baking pan. Bake about 10 minutes or until lightly browned.
Meanwhile, in a small bowl, combine 2 tablespoons of the brown sugar, the salt, curry powder, cumin, and cayenne pepper; set aside.
In a large saucepan, combine water, butter, and the remaining 1 tablespoon brown sugar. Bring to boiling, stirring constantly. Add cashews, stirring to coat. Cook and stir about 2 minutes or until liquid is evaporated. Remove from heat. Add curry mixture; toss gently to coat.
Spread nuts in an even layer in the same baking pan. Bake for 12 to 15 minutes or until golden brown, stirring once. Cool in pan on a wire rack.