noun
macaroni au gratin
A baked dish of macaroni in a creamy sauce, often with cheese, similar to macaroni and cheese but typically with a gratin topping.
from French
今夜の夕食はマカロニグラタンにしよう。
Let's have macaroni au gratin for dinner tonight.
Variant with interpunct; less common but seen in menus or packaging.
From French 'macaroni au gratin', borrowed into Japanese as a dish name.