Wash the mugwort thoroughly and remove excess moisture.
Peel the potatoes and onions, then cut them into suitable sizes.
Melt butter in a pot and sauté the onions and potatoes.
Add the mugwort and continue to stir-fry, then pour in water.
Boil until the potatoes are cooked.
Turn off the heat and blend everything smoothly with a hand blender.
Add milk, salt, and pepper, then mix well.
Heat once more and serve in a bowl.