Steaming (蒸) is one of the most important Chinese cooking methods. Many classic dishes use it: 蒸饺 (steamed dumplings), 蒸蛋 (steamed egg), 清蒸鱼 (steamed fish).
memory
The character has 艹 (grass/plant) on top — think of steam rising from plants/herbs. The bottom part 烝 originally meant rising steam.