In the 54th minute, Leicester wing Varndell collected a sumptuous crossfield kick from London Irish centre Shane Geraghty and grounded in the corner to delight his home crowd.
Eighteen minutes later he took a neat offload from Dylan Hartley and scampered over to seal victory for a Saxons side with an average age of 23 and with only five fully-capped players in their starting XV.
It was a pointed reminder to Ashton of Varndell's predatory skills as the RBS Six Nations get under way on Saturday and ultimately accounted for a vastly more experienced Ireland outfit boasting around 150 senior caps.
Delon Armitage, who for long periods was little more than a frozen spectator on the opposite flank, popped up in the last minute to claim England's fourth and final try and seal a powerful second-half Saxons display.
Gloucester fly-half Ryan Lamb was forced off midway through a bitterly disappointing first half which saw David Paice cross the line but Ireland led 10-8 at the break.
Ireland, skippered by the influential Shane Horgan, edged ahead with a third-minute penalty from fly-half Andrew Dunne but the Saxons' response was initially impressive.
A penalty from Lamb drew Saxons level shortly after but Ireland showed a craft and poise in midfield which at times threatened to tear England apart.
They orchestrated a move which saw the ball pass through five pairs of hands and very nearly breached England's rearguard down the left wing.
The danger cleared and a brief purple patch from the Saxons culminated in London Irish's Paice finding a hole to plough over the line from point-blank range.
Lamb, having taken a knock, was unlucky to see his conversion drift narrowly wide of an upright and with the Gloucester playmaker having departed, Ireland forged ahead.
Isaac Boss, from a scrum, produced a rapier-like offload to Tommy Bowe and he showed blistering speed to scamper over in the right corner despite the best efforts of Saxons full-back Nick Abendanon.
England steadily improved after the break and Varndell's clinical brace edged them ahead before Armitage went over in the left corner in the dying stages.