The final, returning to Carrow Road for the first time since 2019 due to the coronavirus pandemic saw Mulbarton take the trophy home with a late 87th minute winner from Joe Easton.
Wanderers had taken the lead through an Own Goal by Dereham's Ashton Fox but they were pegged back by a Toby Hilliard equaliser 20 minutes from time. However, Wanderers had the final say when Joe Easton found the net 3 minutes from time.
It was Wanderers who made the brightest start to the game and won a free kick when Kieran Smith was fouled, Danny Self floated in the subsequent free kick which found Ben Jones in his noticeable orange boots and fired wide.
Wanderers continued to look the hungrier of the two teams in the initial phases of the game as Cruise Nyadzayo and Ben Thompson were linking up well down the left and saw Nyadzayo skip past Fox but was unable to find any success in the final third.
Match referee Ady George spoke to Derehams Shaun Bammant for a nasty challenge but at this stage was keen to continue the game without the need to brandish his cards.
Derehams first promising opening was when Rossi Jarvis found Bammant but there was no connection from the Dereham man.
It was a cagey opening where clear cut chances were non existent as is often the case in these high pressure finals with so much on the line.
Jones was next to be spoke to by the referee as Dereham began to get at Wanderers.
David Hinton the Magpies captain went down in the box but the penalty appeals were correctly waved away.
Wanderers continued to try and get forward as Nyadzayo had a long range effort before Thompson found Jones with a great ball into the area but there was no final threat to goal in this particular move.
In the games first shot on target Derehams Dion Fray worked Tom Wright in the Wanderers goal who was to be on inspired form all evening.
Dereham had the ball in the net when an Adam Hipperson corner was headed in by Toby Hilliard but the goal was ruled out for an infringement.
Dereham wanted to respond to that set back positively as their next chance saw Hipperson find Luke Johnson out on the right but he scuffed his shot.
The game plan from Wanderers was working very nicely as they were content to let Dereham have possessions and see the game through to goalless at the interval.
Dereham had clearly had a Half Time rally from their management team Adam Gusterson and Olly Willis as they came out for the second half fired up and Hipperson floated in a free kick that saw Fox headed down and Wright needed to make a great save in the Wanderers goal.
In a serious of early Dereham second half chances, Hipperson fired a stabbed shot at Wright who dealt with it well at his nearby post.
A Dereham corner was then floated in and Bammant chested down and over the bar.
A delay to proceedings followed as Bammant and Wanderers Toby Oliver clashed heads requiring on pitch presence from both club physios.
When the game re started Dereham continued their chances but again found Wright in wonderful form as he got down well to keep out Hipperson.
The deadlock was broken when Danny Self floated in a free kick into the box that Fox was unable to prevent coming off his leg and finding the net. Wanderers led and it sparked wild scenes of celebration with the entire dugout coming onto the pitch to celebrate.
A cup final that had that extra special feeling for Wanderers as they occupied the Norwich City dressing room and Norwich City dugout and roared on by their massive contingent of fans in one half of the City Stand, the village of Mulbarton began to believe it was their night.
However, 6 minutes later Wanderers were pegged back when Dereham scored from a brilliant move that saw Hipperson produce a great pass to Johnson who then crossed and Hilliard slid in to level the scores with 20 minutes remaining.
Dereham sensed it was now their night as they upped the Anti with Rhys Logan firing wide from 25 yards out.
A Logan corner was then stunningly fired over in acrobatic fashion from Hilliard.
Wright was then called upon again to superbly deny Rossi Jarvis with a great block. Wright would then go on to win the man of the match award.
A closely contested tested final which attracted a wonderful 4 figure crowd of 1197 for Norfolk County FA's biggest night of men's football of the year with Mulbarton Belles to follow on Wednesday night in the Women's Cup Final at Carrow Road.
This final was not done yet though and the decisive moment came when Smith knocked on to captain James Page who found Easton who volleyed beyond Joseph Rider in the Dereham Town goal to again spark wild scenes of celebration from players, staff and supporters.
There was no way back for Dereham and after the disappointment of losing last years final to Gorleston. Mulbarton Wanderers proudly celebrated their Senior Cup triumph. A village together as one in the biggest ground in Norfolk.
Next up is the turn of Mulbarton Belles in the Women's Cup Final vs Wymondham Town again at Carrow Road on Wednesday night, 7.45pm.
Mulbarton Wanderers: Wright (GK), Smith, Doggett, Page (C), Easton, Oliver, Nyadzayo, Self, Thompson, Jones, Henry. Subs: Fancett, Beaumont, Matthews, Altay, Foreman
Dereham Town: Rider (GK), Johnson, Fray, Jarvis, Castellan, Fox, Logan, Hinton (C), Bammant, Hilliard, Hipperson. Subs: Fisk, Linford, Smith, Zielonka, Thurston.
Attendance: 1197
Report by Darrell Allen
Referee: Ady George