First you need to get the Club weapon or Hammer weapon.

The first opportunity to find the Club is in Level 3: Cemetery Hill. When jumping down the left side of the hill with the rolling rocks it's in a chest.
The Hammer is unlocked by redeeming the 3rd Chalice in the Hall of Heroes.

Severed Hands are running around the floor in Level 2: The Graveyard & Level 5: Return to Graveyard. Load up one of these levels and attack a severed hand that runs around the floor with the Club / Hammer. This will smash the hand and unlock the trophy.