Thinly slice the potatoes and soak them in water to remove excess starch. Drain well. Trim the asparagus, peel the lower halves, and cut into 3–4 pieces. Separate the bottom third from the rest.

Mix the seasoning ingredients (sugar, miso, sake, and mayonnaise) in a bowl.

Heat salad oil in a pan over medium heat. Add ground pork and cook until the color changes. Add potatoes and the bottom third of the asparagus, stir to coat with oil, then cover and steam on low heat for 2 minutes.