By GINIA BELLAFANTE

Touting the virtues of low-cal brownies on national television can provide an actress with only so much fulfillment. Thankfully, renowned thespian a.k.a. Weight Watchers spokeswoman LYNN REDGRAVE now has something deliciously meaty to sink her teeth into. She's currently touring the country with a one-woman show, Shakespeare for My Father: The Life and Times of an Actor's Daughter, a tribute she scribed to the legendary Sir Michael Redgrave. "I don't know whether I should have the presumption to call it a play," says Redgrave. "It's not actually something that could be performed by anybody else. It's quite personal--a search for the emotionally absent father."