The 24-year old Ashanti Gold forward gave the Black Stars B the lead on the half hour mark to set the tune for an impressive victory under the floodlights over the Elephants.
Augustine Okrah's fierce shot just inside the penalty area was parried inside the six yards area, the loose ball came of Mumuni following an attempted clearance by Koffi Kouame.
The Ivorians should been in front on the 20th minute when David Fofana's drive from distance went inches wide off Eric Ofori's goal.
The 2017 champions increased their lead at minute after the restart when Mumuni Shafiu connected with a inch perfect left-wing cross to head home from close to increase Ghana's tally.
The Ghana captain completed his hat trick four minutes after the break with a poacher's header from 12 yards out.
The deflated Elephant struggled to create any meaningful opportunity until the 72nd minute when Aboubacar Doumbia powered home the consolation from a freekick to make a respectable 3-1 score.
Maxwell Konadu's charges will face the winner between Mali and hosts Senegal in Sunday's Grand final at the refurbished Lat Dior Stadium in Thiés.[cafonline]