Perhaps it is coincidence, but growing up in Worcester, Massachusetts, Worcestershire sauce was a common ingredient in our home. I have been making this soup since I was a college student in the 1970s because the ingredients were always on hand.
There is something very basic about this simple preparation and the addition of the Worcestershire at the end. That little dash is what gives this soup it's unique flavor that many people struggle to identify.
In small saucepan, combine diced potates, onion, salt and boiling water.
Simmer, covered 8 minutes. Set aside and do not drain.
Don't make the same mistake I did once and automatically drain the potatoes, or there goes your soup.
In a medium saucepan melt butter. Stir in flour until smooth. Gradually add milk, blending until smooth. Simmer, stirring constantly until thickened. Remove from heat.
Add cheese and stir until it melts. Add the undrained potatoes and onion. Finish with the Worcestershire sauce.
Heat but do not boil. Sprinkle with paprika or chives (optional)