Premise: It's the modern day, and humans have various magical abilities through a runic magic system. One of these abilities, which I'm currently trying to visualize the implications of, is called Hammergate (short for "Hammerspace Gate"). It essentially grants the bearer access to their own 7 foot wide, 7 foot tall, and 3 foot deep pocket dimension that they can open a portal to at will, though only once every 10 minutes (exact cooldown time subject to change). The portal, which is as tall and wide as the pocket dimension itself, stays open for as long as they're within 3 feet of the portal, and anything they put inside there will stay there, in that pocket dimension, until taken out at a later time. Additionally, and crucially to this question, whenever the portal isn't open, time doesn't pass inside that pocket dimension. If you drop a ball inside of it and then quickly close it before it hits the ground, the ball will resume falling to the floor as soon as the portal is re-opened at a later time.
One of the things I realized this allows for is essentially infinite shelf life. You can store something in there indefinitely, and it will never get stale, rot, melt, spoil, or change state in any way whatsoever until you open it up again. And this gave me an idea for a way I could show this impacting the world of my story.
If, hypothetically, there were a food ingredient that would be absolutely delicious, but isn't served in any real restaurant because it's near physically impossible to get the ingredients to the customer before they go bad or noticeably reduce in quality in some other way, then suddenly this pocket dimension storage power would make that possible, at least as a luxury even if the power isn't prevalent enough to make it easily available. But the issue is that I don't know if any such foodstuff exists.
Is there a food ingredient that would be delicious, but goes bad too quickly to be served at a restaurant? Something that time-freezing storage would suddenly make a viable cooking ingredient?