2 lbs. asparagus, or 2 pkgs. frozen asparagus, thawed
3 c. potatoes, sliced
1 c. leaks, sliced
1/2 c. onions, sliced
2 qts. chicken broth
1 tsp. salt
1/4 tsp. white pepper
1 egg yolk
1/2 - 1 c. heavy cream
1/2 stick butter

Wash fresh asparagus, cut away the tough white part and discard. Cut off 12 to 14 1/2" pieces from the tips of fresh asparagus and reserve. Slice the remaining fresh or frozen asparagus in 1" pieces. Saute stems, leeks and onions in 1/2 stick butter for 5 minutes, do not brown. Combine in a saucepan with the potatoes, leeks, onions, broth, salt and pepper. Bring to a boil and cook over low heat for 35 minutes. Puree in an electric blender, then strain. Return to the saucepan and add the reserved tips and add a small amount of butter, if needed, for taste. Cook over low heat for 10 minutes. Beat the egg yolk and cream in a bowl; add a little of the hot soup, stirring steadily to prevent curdling. Return to balance of the soup. Heat, but do not let boil. Serve with a couple of tips in each bowl. Add more broth if too thick.