Icon or kitsch? Betty Crockera cooking doyenne invented in 1921 to help peddle Gold Medal flouris both. Susan Marks's Finding Betty Crocker, due out next month, is a lively quasi-biography that asks, Just what does it mean to be a happy homemaker? Whether teaching women in the '30s about "Foods Men Like" or telling them how to stretch wartime rations, the Betty Crocker radio programs reached millions; the launch of her cake mixes in 1952 helped usher in a new era of convenience foods. Despite a few dark momentsin 1972 NOW filed a lawsuit attacking Betty's image as both racist and sexistBetty Crocker emerges as a true advocate of the hard-working housewife. Not bad for a woman whose constantly changing portrait suggests someone with a serious identity crisis.