An early try from Darren Sweetnam had put Munster ahead before the hosts roared back just before the break when back row Macauley Cook went over for a slender 10-8 lead at the break.
The second half exploded into life as hookers Matthew Rees and Mike Sherry exchanged quick-fire tries before young centre Garyn Smith tore away to send the home crowd into raptures.
Man-of-the-match Rhys Patchell then scored a superb solo try to wrap up the bonus and despite a late Munster effort a penalty from Jarrod Evans on the final whistle wrapped up maximum points and moved Cardiff Blues level with Ospreys in the league standings.
On a cold Friday night in the Welsh capital, it was Munster that made the brightest start as centre Rory Scannell and skipper Billy Holland made early yards up the middle and won a penalty that Ian Keatley slotted over for a third minute lead.
Moments later another break from Scannell again splintered the home defence and, with Cardiff Blues back-tracking in defence, the ball was spun wide right to wing Sweetnam to touch down.
Fly half Patchell reduced the arrears with a well struck penalty from out wide, after a huge home scrum had forced the Irish province back to huge cheers.
Visiting fly half Keatley produced a neat show and go to make a slicing line break and cause alarm, but a knock on stopped the visiting attack before it built any momentum.
The home side were being pinned back for long periods in the opening quarter of the match with the odd foray into the Munster half as Fish and a neat grubber kick in behind by Blaine Scully looked to spark the attack.
When they did click it looked set to pay dividends as young centre Smith rattled past men down the middle and quick ball allowed Patchell to jink his way to the line only for his final pass to Fish to be spilled forward to the anguish of home fans.
Back row Jenkins forced a penalty just yards from the Munster line to wild applause and the home side opted to scrum. But after two attempts a pass wide failed to find hands and Billy Holland stripped ball to allow Munster to clear.
Lloyd Williams and Lee-Lo rolled out of tackles to fire another long-range attack before Navidi broke the line and drew the final man before popping the ball to Cook to stride over unopposed. Patchell’s conversion gave the home side the lead for the first time.
The response from Munster was impressive as they worked their way up field before kicking to the corner. A number of drives went close before Munster went wide only for Scully to fly out the line and pick off the final pass by racing away.
The teams exchanged penalties at the start of the second half before a second home try as a quickly taken lineout caught Munster napping and Rees was over. Patchell added the extras from the touchline for a 20-11 lead.
Back came Munster and within four minutes were back in the game as a huge lineout was driven over and Mike Sherry scored.
However, a breathless period was then complete as young centre Smith ripped the ball from his man and raced away to score a third home try to wild celebrations.
Johnny Holland ate into the lead with a penalty before a tense final ten minutes played out in front of enthralled Arms Park crowd.
The game looked over when a classy Patchell spotted a gap and was over after silky run to the line.
O’Donoghue rumbled over the line with less than 60 minutes left to threaten late heart-break after a period of sustained Munster pressure.
But the visitors were to leave empty-handed as they were penalised as they looked to run the ball from deep in one last attack and up stepped Evans to nudge over the kick and start the celebrations.
03m Keatley p 0-3
07m Sweetnam t 0-8
11m Patchell p 3-8
33m Cook t Patchell c 10-8
44m Patchell p 13-8
47m Keatley p 13-11
49m Rees t Patchell c 20-11
53m Sherry t Keatley c 20-18
55m Smith t Patchell c 27-18
68m J Holland p 27-21
74m Patchell t Patchell c 34-21
79m O’Donoghue t J Holland c 34-28
80m J Evans p 37-28
Cardiff Blues: 15 Dan Fish, 14 Blaine Scully (J Evans 63), 13 Garyn Smith, 12 Rey Lee-Lo, 11 Aled Summerhill, 10 Rhys Patchell, 9 Lloyd Williams (Jones 76); 1 Brad Thyer (Davies 69), 2 Matthew Rees (Dacey 50), 3 Salesi Ma’afu (Filise 40 (Ma’afu 73)), 4 Cam Dolan (Vosawai 69), 5 Josh Turnbull, 6 Macauley Cook, 7 Ellis Jenkins, 8 Josh Navidi
Replacements: 16 Kristian Dacey, 17 Thomas Davies, 18 Taufa’ao Filise, 19 Lou Reed, 20 Manoa Vosawai, 21 Lewis Jones, 22 Jarrod Evans, 23 Gavin Evans