牛肉 is beef, 炒 is stir-fried, 牛肉 is beef (牛 is cow, and 肉 is meat), and 西蘭花is broccoli (西 is western and 蘭花 is orchid). So 牛肉炒西蘭花 is beef stir-fried western orchid.
About This Dish
Beef and broccoli is a classic Chinese-American dish created by immigrants who substituted broccoli for Chinese broccoli (gailan), so you could call it beef and American Chinese broccoli.