For example, I've heard that Sloppy Joes were invented during the Great Depression when people tried to stretch their ground beef by adding ketchup or tomato sauce to it. Is there any truth to this? Are there any other examples?
We have a dish in Québec called "Pouding chomeur" (litterally "Unemployed man's pudding") which is said to have it's roots in the troubles of 1929 (reference). It's still quite popular and widely eaten today, typically done with brown sugar, or even better maple syrup.
Clara's meals from the depression are authentic and good