Another fun one from the “Snow Eggs” recipe in 魔女館へようこそ:
For the kana-challenged, that’s “arumi no batto”. The context is retrieving the poached meringue from the water with a skimmer, and placing it either onto a plate or an “arumi no batto”.
Answer below the fold…
It’s taken from the French bateau, and most often seems to refer to one of these (amusingly, the picture comes from a site that rendered it as “vat”):
…except when the phonetically-identical word is being used to refer to one of these: