Offley & Stopsley - from the Eastern League Division 1 - were level with Luton Town of the FAWPL until just after the half-hour mark at Bedford Town FC.
But Nicola Henman then broke the deadlock, slotting in from close range after a delivery by Dionne Manning.
Despite the two-division difference. the underdogs were close to levelling immediately and went in at the break just the single goal down.
But just 2 minutes after the restart and the lead was doubled, Zara Carroll tapping in the rebound after Amy Summerfield's powerful header was saved from a Erica Byron corner.
Luton made sure of retaining the trophy with a third goal 7 minutes from time, Jodie Bellinger scoring with a clever flick from close range.
Photo - Gary Bailey