Peel potatoes (not required for Yukon Golds), then dice into bite sized pieces. Boil with 2 tbsp. salt. until el dente. Let Cool.
Boil Eggs starting with cold water and eggs in the pot. Bring to a hard boil, remove pan from heat. Cover with lid for 15 minutes. Remove eggs and rinse in ice cold water. Shake pan to crack shells. Additional rinse. Sit in cold water for 2 minutes, shell eggs.
Mix mayonnaise, yellow mustard and grey poupon.
Cut up onions and celery into small pieces.
Slice the radishes thinly.
Add onions, celery, radishes salt and pepper and 8 sliced hard boiled eggs into mayonnaise & mustard mixture.
Gently fold in cooled potato pieces, covering with the mayonnaise mixture.
Add remaining hard boiled eggs, sliced, to top of bowl as a garnish.
Let stand in refrigerator until time to serve.