"I know this recipe was given to my Aunt by her mother-in-law when she was a young woman in the early 1900's. It is a quick-fix meal that uses canned oysters. This makes a good hearty light meal to end your day. Serve with a nice bread or in bread bowls with chunks of different cheese. My Aunt used smoked shucked oysters plain shucked oysters. She also cooked this until the edges curled and the center firmed."
Combine 3 cups water and potato in a Dutch oven over medium heat; bring to a boil and cook until the potato is soft, 4 to 5 minutes.
Stir the butter into the potato cubes and cook an additional 5 minutes.
Whisk the flour and 1/3 cup water together in a small bowl until smooth; stir into the potato mixture.
Mix the oysters with their liquid, whipping cream, mushrooms, powdered milk, salt, and Worcestershire sauce into the potato mixture; cook until warmed through, 5 to 10 minutes. Thin with additional water as needed, adding 1/4 cup at a time, stirring continually, until you get your desired consistency.