For the soup: Melt the butter in a large pot over medium-high heat. Add the carrots, celery, onions, a good pinch of salt and a few turns of pepper and cook, stirring often, until the vegetables soften, about 10 minutes. Add the garlic and nutmeg and cook, stirring, until fragrant, 2 more minutes.
Stir in the stock, herbs, bay leaves and potatoes. Increase the heat to high and bring to a boil. Reduce the heat to a simmer, then cover and cook for 40 minutes.
For the knoephla: Meanwhile, whisk together the flour, baking powder, salt, a few turns of pepper and the nutmeg in a medium bowl. Stir in 1 cup (236 grams) water and the egg and mix to form a shaggy dough. Turn it out onto a clean work surface and knead it for a few minutes, adding flour as needed, until you have a smooth and stiff dough. Roll it into a 1/2-inch-thick blob, then cut into 1/2- to 3/4-inch squares, dusting with flour so they don't stick together.
When the soup has 20 minutes left of simmer time, add the knoephla directly to the soup and continue to simmer.
Stir in the cream. Taste and adjust the seasonings as desired. Remove the bay leaves before serving. Enjoy!