The attacker attacked the Morrisons Dairy convenience store on King Edwards Drive in Bilton, Harrogate, just after staff opened it yesterday morning.
Police said the robbers grabbed two trays of e-cigarettes when they entered the store.
Store employees confronted him, but the robber punched him in the face and threatened further violence before fleeing with the e-cigarette.
Police are appealing for information about a man carrying a backpack on the street near the store at the time of the robbery.
A spokesperson said: “We are appealing to anyone who was in the area before or after the incident and saw a man with a backpack on the street surrounding the store to contact us.''
We are also appealing to anyone who may have recorded CCTV, doorbell video cameras or dash cams of the suspect who was driving by at the time. ”
Anyone with information is asked to pass it on to Harrogate CID by emailing harley.wilkinson2@northyorkshire.police.uk or by calling 101.
If you wish to remain anonymous, information can be passed to Crimestoppers on 0800 555 111.
When you call, please quote reference number 12250010366.
