It was not until 1992 did scientists realize that light beams with a helical phase carry orbital angular momentum (OAM) [1].The discovery of optical OAM has spurred a wealth of applications such as high-speed optical communications, optical spanners and spinorbit angular momentum coupling [2-4].To date, the majority of OAM beams are temporally static, i.e., the OAM does not vary in time.Recently, Rego et al.[5] generated extreme-ultraviolet self-torqued beams in high-harmonic generation driven by timedelayed pulses that differ by one unit of OAM.The temporal OAM variation could potentially be utilized to manipulate nanostructures and launch chiral excitations on ultrafast time scales [6].