Bad Newbie actions, need help sorting it out

Hello,
I have a Sony ZV-1 that needed a firmware update, and the only way to do it was via Windows (no support for M1 chip). Okay, I installed Parallels, installed Win11, ran the firmware update, everything worked.

Then I did the bad stuff.

I was done with Windows, so I uninstalled Parallels. OOPS. Should've uninstalled Win11 first! Reinstalled Parallels, which now referenced Windows 11 (1). Found out how to delete Windows 11 (1), that worked just fine. But the original Win11 is still on my Mac *somewhere*, and I can't find a way to delete it. I don't want to re-install Parallels unless absolutely necessary. There isn't a Windows partition on my machine, so I have no idea where the 15GB is - that's the difference in HD space after doing the install/uninstall.

Any ideas how I can free that space up, and where it might be?