Sauté the onion, garlic and 2/3 of the parsley in 2 tablespoons of butter. Then dust with flour and carefully add the milk and cream, stirring constantly. Then slowly pour in the broth.
Let the soup simmer for about 10 minutes and then finely puree with the hand blender. Season to taste with salt, pepper and nutmeg. Add a pinch of sugar.
Toast 1 tablespoon of sugar and the carrot strips in 1 tablespoon of butter in a non-stick pan until they turn a slightly golden color.
Arrange the soup on plates and put a few strips of carrots on top, then sprinkle with a little parsley.