Cream of asparagus soup (spargelsuppe)

1 lb white asparagus
1 tablespoon salt
1 teaspoon sugar
1/2 stick unsalted butter
1 cup milk
2 tablespoons flour
2 egg yolks
1/4 cup heavy cream
water
chervil
nutmeg
ground white pepper

Peel the asparagus, reserve the peels and boil them in approx. 3 cups water with salt, sugar and some of the butter for 15-20 minutes. Remove the peels, cut the asparagus into 1-inch pieces add to the asparagus broth and simmer for 20 minutes. Pour the soup through a sieve and reserve the asparagus pieces and 2 cups of the broth. Combine the reserved broth with the milk. In another cooking pot melt the butter and whisk in the flour. Let the flour get a light yellow color. Whisking the flour constantly while carefully pouring in the milk-broth-liquid. Keep whisking so you don`t end up with lumps in the soup. Let simmer for about 5 minutes. Season with salt, pepper, and nutmeg. Take of the stove and let stand for 3-5 minutes. In a small bowl whisk together the yolks and cream. Carefully stir cream into the soup. Return the reserved asparagus pieces into the soup. (Or separate the pieces with the top tips from the other pieces. Strain the pieces except for the tips through a sieve, stir into the soup and later add the pieces with the tips to the soup). Garnish with chervil. If you like you also can top the individual servings with either thin slices of smoked salmon or smoked raw ham.