Definition & Meaning of "{one's} cake [is] dough"

What is the origin of the idiom "one's cake is dough" and when to use it?

The idiom "one's cake is dough"may have originated in medieval times, when cakes were sometimes made with yeast, and if the yeast failed to rise, the cake would be ruined and the dough would be wasted. The phrase has been in use in English since at least the early 19th century, and it has been applied to a wide range of situations, including personal and financial struggles, as well as business and political ventures. In general, the phrase is used to describe a situation where someone has invested time, effort, or resources into a project or goal, but where the outcome is disappointing or unsuccessful.