Peel and wash the potatoes and cut into small cubes. Peel and finely dice the onion. Heat butter in a pot. Sauté diced onion for 1-2 minutes. Add potatoes, steam for 1-2 minutes, then add peas.
Deglaze with broth and 100 g whipped cream.
Season with salt, pepper and nutmeg and simmer covered for 15-20 minutes until the potatoes are soft. Wash the chives, shake dry and cut into thin rolls.
Puree the soup and season to taste again. Add half the chives and simmer for another 2-3 minutes. Arrange soup in bowls and draw streaks on the surface with 5 tablespoons of whipped cream. Sprinkle with remaining chives and serve immediately.