A mallet is a tool that looks like a hammer but with a larger, usually wooden, head. It is used for striking or pounding objects, but often without causing damage. Full definition
PLACE chicken between two sheets plastic wrap; pound with meat mallet or heavy pan to flatten. (cabotcheese.coop)
If necessary, pound breast with mallet for uniform thickness. (letsgothin.com)
Noticing that one plate had a fairly severe stress fracture, I placed it in a cloth tote, and gently tapped on the back with a rubber mallet until it cracked. (styleathome.com)