cudgel one's brains

/K AH1 JH AH0 L W AH0 N EH0 S B R EY0 N Z/
verb
  1. 1

    To think hard and try to remember something.

Source: https://en.wiktionary.org/wiki/cudgel%20one's%20brain, https://en.wiktionary.org/wiki/cudgel%20one's%20brains