Preheat the oven to 400 degrees F.
In a small bowl combine Parmesan cheese, cashews, lemon zest, garlic powder, and pinch of salt, and set aside.
Place the broccoli on a baking sheet. Drizzle with butter and toss. Season with salt and pepper, to taste.
Roast in the oven until broccoli begins to caramelize, about 20 minutes. Remove, and toss the broccoli with the cashew mixture. Serve warm.