In both Councils, the legislative and the executive one. We do have a European Prosecutor set up without several members (some joined later, under more pro-inyegration governments) so for things to move fast enough we probably can't wait for treaty change. We should still do it though, and we have the blueprint.
https://institutdelors.eu/en/publications/sailing-on-high-seas-reforming-and-enlarging-the-eu-for-the-21st-century/