MEATBALLS:

1 tbsp. butter
1/2 c. finely chopped onions
2 slices homemade-type fresh white bread with crusts removed
2 tbsp. heavy cream
1/3 lb. lean boneless beef
1/3 lb. lean boneless pork
1/3 lb. lean boneless veal
3 flat anchovy fillets, drained, rinsed in cold water and coarsely chopped, or substitute 1 tsp. anchovy paste
2 tbsp. finely chopped parsley
2 eggs
1/2 tsp. finely grated lemon peel
1/2 tsp. salt
1/4 tsp. freshly ground black pepper

Ground together 3 times.

Melt 1 tablespoon of butter in a small skillet over moderate heat and in it cook the chopped onions for 5 minutes, or until they are transparent but not brown. Remove the skillet from the heat.

Tear the bread into small pieces into a large bowl; add the cream and mix well. Add the onions, ground meat, anchovy fillets or anchovy paste, parsley, eggs, lemon peel, 1/2 teaspoon salt and black pepper. Knead vigorously with both hands until the ingredients are well combined, then put the mixture through the finest blade of a meat grinder. Moistening your hands lightly with cold water, shape the mixture into 8 large meatballs about 2 inches in diameter.;

POACHING LIQUID:

2 qt. water
1 med.-size onion, peeled and pierced with 1 whole clove
1 sm. bay leaf
1 tsp. salt

In a heavy 6 to 8-quart saucepan or soup pot, bring the water, whole onion, bay leaf and 1 teaspoon of salt to a boil over high heat. Boil, uncovered, for 10 minutes. Then reduce the heat to low and drop in the meatballs. Simmer uncovered for 20 minutes, or until the Klopse rise to the surface of the water. With a slotted spoon, transfer them to a deep heated platter and cover them with aluminum foil to prevent their darkening upon exposure to air. Strain the poaching liquid through a fine sieve into a bowl and put is aside.

SAUCE:

4 tbsp. butter
4 tbsp. flour
3 tbsp. fresh lemon juice
1 tbsp. capers, drained
2 egg yolks
2 tbsp. sour cream

In a heavy 10 to 12-inch skillet, melt 4 tablespoons of butter over moderate heat. When the foam subsides, stir in the flour. Pour in 3 cups of the poaching liquid and bring it to a boil, beating constantly with a whisk until the sauce thickens and is smooth. Reduce the heat to low; add the lemon juice and capers and simmer uncovered, stirring occasionally, for 15 minutes.

In a small bowl break the egg yolks up with a fork, then stir into them 1/4 cup of the simmering sauce. Whisk the mixture back into the skillet and stir in the sour cream. Taste for seasoning. Add the meatballs and simmer, basting from time to time, until they are thoroughly heated. To serve, return the meatballs to the platter, and pour the sauce over them.