Put the water in a small frying pan and bring to a boil. Add the dashi stock granules, and thinly sliced onion. When it comes to a boil, add the mirin and soy sauce and simmer for 3 minutes.
While it's cooking, chop the scallions finely, and serve rice in a bowl.
When the onion has cooked through, add the pork and cook through while flipping. As soon as the pork changes color, turn off the heat.
Put the mixture evenly on top of the bed of rice. Add the chopped scallions and squirt mayonnaise on top.
Story Behind this Recipe
My children were asking for a meaty rice bowl with scallions mayonnaise, so I prepared this with ingredients I had at hand.
Shabu-shabu meat is very thin, so add it to the pan once the onions have cooked as the meat will cook through quickly. I didn't cut up the meat, but it may be best to cut into bite sizes if serving to children.