Floury new potatoes and a rich avocado sauce go exceptionally well together in this dish. This is a quick gratin that doesn't need to be baked in the oven.
I needed a way to use up and over-ripe avocado, so I used it to make sauce for gratin.
If avocado is heated it won't become brown even after cutting, so you can prepare the sauce in advance if you like. Take care not to overcook the avocado or else it will become bitter.
Enjoy Japanese food around the world.