Why "old fashion way" isn't quite right
What kind of error is it?

It is a phrase error due to incorrect usage or outdated colloquial expression. The typical phrase intended is "old-fashioned way", which refers to doing something in a traditional or time-tested manner.
Why do people make this mistake?
People might make this error due to a misunderstanding or mishearing of the phrase over time. Sometimes casual speech or regional dialects contribute to the adoption of non-standard phrases.
What is correct?
The correct phrase is "old-fashioned way". It properly uses the adjective "old-fashioned" to describe the manner in which something is done, emphasizing tradition or antiquity.
Examples of correct usage
- He prefers to write letters the old-fashioned way, with pen and paper.
- We cooked the meal the old-fashioned way, using Grandma's recipe.
- Despite technology, some people enjoy brewing coffee the old-fashioned way.