On parchment paper-lined or greased rimmed baking sheet, toast cashews in 350°F (180°C) oven until fragrant and golden, about 10 minutes.
Meanwhile, in large bowl, combine 2 tbsp (25 mL) of the sugar, salt, curry powder and cumin; set aside.
In saucepan, bring water, remaining brown sugar and butter to boil, stirring constantly. Add cashews, stirring to coat; simmer until no liquid remains, about 3 minutes. Add to spice mixture; toss to coat well.
Spread nuts on same baking sheet; roast until coating is dry and slightly golden, about 10 minutes. Let cool on pan on rack. (Make-ahead: Store in airtight container at room temperature for up to 1 week.).