Okay, but what if you already cut into that beautiful butternut? Now the rules change. Once you slice a hard squash open, you’ve broken its armor. The exposed flesh is now a moisture-rich magnet for bacteria. So, wrap it tightly in plastic wrap and put it in the fridge. Use it within a few days.
Same goes for leftover cooked squash. If you roasted a tray of butternut cubes last night? Fridge it. It’s a leftover now, and leftovers are fridge residents. Think of it like this: the whole squash is a castle; cut squash is a room with no roof.
