To cook food by steaming with hot vapor; often used for foods like potatoes or rice (synonymous with 蒸す).
じゃがいもを蒸かしてからバターをのせて食べた。
I steamed the potatoes and then ate them with butter on top.
蒸かしたさつまいもは甘みが増しておいしい。
Steamed sweet potatoes become sweeter and are delicious.
お米は炊く以外に蒸かしておこわのように作ることもある。
Besides boiling/steaming rice in a cooker, you can steam it to make something like sticky rice.