Easy area to get this achievement:
At the end of "forsaken city", when you're about to destroy the soul cage. The enemies keep spawning until it's destroyed.
When you're holding
to destroy it, you earn the required souls. As soon as your amulet it powered up, let go off
(so you don't destroy the soul cage).
Do your amulet attack, and recharge.
do this 3 times, and you get the achievement.
Backup link to video: https://1drv.ms/v/s!AgeRx076fObninCso53iv-Wezgow