Nikujyaga

Peel and cut the potatoes into large chunks, slice the onion into wedges, and cut the beef into bite-sized pieces. Rehydrate the shiitake mushrooms in warm water for 15 minutes if using dried, then trim the stems.

Heat a thin layer of oil in a heavy-bottomed pot over medium-high heat and sear the beef pieces until lightly browned on all sides. Remove the beef and set aside.

In the same pot, add the onion wedges and sauté over medium heat until they begin to soften and turn translucent, about 3 minutes.

Return the beef to the pot and add the potatoes and shiitake mushrooms. Pour in enough water to just cover the ingredients, approximately 2 cups.

Add the soy sauce, mirin, and sugar to the pot and stir gently to combine. Bring the liquid to a boil over medium-high heat.

Once boiling, skim off any foam or impurities that rise to the surface using a ladle or spoon.

Reduce the heat to low, place a drop lid (otoshibuta) or a circle of parchment paper directly on the surface of the stew, and simmer gently until the potatoes are tender and the braising liquid has reduced and intensified in flavor.

Remove from heat and allow the stew to rest for 5 minutes so the ingredients absorb the remaining braising liquid before serving.