Case sparks best boss battle

NEWS that socialite Libbie Mugrabi has been charged with threatening her housekeeper with a knife has led to a round of mensch one-upmanship among those who also have a household staff, it seems.

When the topic quickly came up at Candace Bushnell’s birthday dinner at Hutong on Manhattan’s Upper East Side Thursday, one Uptown lady was heard to remark: “I would never treat my housekeeper that way. If we order Sant Ambroeus, she gets it, too!” Really puts the “saint” in Sant Ambroeus . . .

(Mugrabi pleaded not guilty to the charges on Wednesday.)

We hear it was the second bash to celebrate Bushnell’s 64th birthday. Apparently the “Sex and the City” writer had an intimate dinner at the new London import, which has taken over the former Le Cirque space, on her actual birthday, Dec. 1.

But on Thursday, she and publicist Anna Rothschild hosted a larger soiree, starting with a 20-person seated dinner that brought out former “Real Housewives of New York City” star Ramona Singer, socialite and philanthropist Jean Shafiroff, Grimanesa Amorós, Patty Raynes, Laurie Durning, newlyweds Danny Baker Jr. and Petra Khashoggi, and others.

Cuba Gooding Jr. and longtime lady friend Claudine De Niro were spotted having what appeared to be a business dinner date across the room. She told us, “For the record, I am not at this restaurant [because] of [Rothschild],” who happens to be the swanky eatery’s new flack.

The party later moved to the grand opening of the restaurant’s late-night lounge, the Shanghai, where “My Unorthodox Life” star Julia Haart arrived solo, as Singer ordered up vodka sodas. And, despite not being there because of Rothschild, De Niro and Gooding Jr. were at the lounge discussing his new tech venture, Veuit.

The party ended around midnight with birthday cake.