Instead of crushing the large dried pepper when player is not holding the pestle or the player is not holding the wooden bowl:
say "You can't do that with your bare hands."
EDIT: oops, should be an “or”, not “and”, if you want the player to be holding both (I think I’ve been confusing mortars and pestles all this time!) Thanks to @StJohnLimbo for catching that and sending me a DM to avoid slinging egg in my face