Definition of motherhood and apple-pie in US English:

motherhood and apple-pie

noun

  • (In allusive and similative use) something regarded as so unquestionably good as to be beyond criticism; specifically (usually ironic or with pejorative connotations) something exemplifying traditionally wholesome American values. In later use, frequently attributive or as adjective: representing irrefutable and unquestionable goodness and integrity.

Origin

1970s; earliest use found in Forbes.