Steam or boil the broccoli till tender but still crisp-about 7 mins. Drain, and arrange broccoli on a serving platter.
While the broccoli is cooking, melt the butter in a small frypan or pot over medium heat. Mix in the brown sugar, soya sauce, vinegar, pepper and garlic. Bring to a boil (make sure it doesn’t burn) then remove from the heat.
Mix in the cashews, and pour the garlic butter sauce over the broccoli. Serve immediately.