If you are in the oven with potatoes in Argentina you are in a situation that is very complicated, very difficult and possibly without a solution.

Just being in the oven isn’t enough – in Argentina potatoes are in the oven with you! Possibly the potatoes being there means that the oven is going to be hot for awhile and your problems aren’t going to go away easily.

The addition of “with potatoes” (con papas) is key.
If you’ve already added potatoes to the oven, you’re committed—you’re not getting any dish out early. Your fate is sealed. You’re really in trouble.

In everyday life, Argentines use this phrase whenever things have spiraled past the point of return.

Some examples may be when you have a presentation in 10 minutes and you forgot the USB with no hope of getting it in time. Or you forgot about an appointment that is across town in 10 minutes. You are definitely in the oven with potatoes.

It may be a bit dramatic but it captures the deep cultural love of expressing disaster poetically.