1/2 c. butter
1/2 c. finely chopped onions
5 med. potatoes, peeled & grated
1 1/2 c. water
2 tsp. salt
2 c. hot milk
1/2 c. cold milk
1 egg yolk
Pepper & salt

Melt butter in heavy pan over low heat. Add onions, stirring until tender. Add potatoes, water and salt. Cover pan and cook until potatoes are tender. Drain. Reserve liquid. Press potatoes through sieve and add to liquid. Add hot milk and stir well. Combine cold milk and beaten egg yolk. Add slowly to warm soup stirring constantly. Add pepper. Reheat slowly but do not boil.