Peel and dice the potatoes into small pieces. Place them in a large pot with the water, salt, and MSG.

Cover and simmer until the potatoes are completely tender and mushy.

Using a whisk or beater, transform the soft potatoes into a smooth puree directly in their cooking liquid.

While the potatoes cook, melt the butter in a heavy-bottomed pan. Add the chopped onions and cook until golden but not browned.

Sprinkle the flour over the golden onions and cook for a few minutes, stirring constantly to make a roux.

Heat the milk separately, then gradually add it to the onion mixture, stirring constantly to prevent lumps.

Let this sauce simmer for about 10 minutes until smooth and thickened.

Combine the thickened milk mixture with the potato puree.

Add the cream and gently heat the soup without boiling.

Season with additional salt if needed and white pepper to taste.

Serve hot, garnished with freshly chopped chives or scallion tops.