The 37-year-old turned in an impressive performance, which was full of neat tricks and clever passing, and will surely be a major asset to the Pilgrims in League Two next season if a deal can be agreed to keep him at York Street.
It took 13 minutes for the Pilgrims to take the lead against an inexperienced Newcastle side that included just three players with first-team experience for the Magpies.
Former Nottingham Forest man Jason Lee flicked on for Carruthers to flick past Tony Caig in the Newcastle goal. Carruthers, a summer signing from Macclesfield, hit the second seven minutes later with a similarly deft finish following Chris Holland's through-ball.
A Mark Greaves header made it three before Gascoigne, who was wearing his famous number 19 shirt, made his first telling contribution, a drive towards the Newcastle box and a neat lay-off for Carruthers to complete his treble, while a Magpies outfit that included the highly-rated Michael Chopra barely managed a shot on goal.