lady who lunches; The multitasking mom and accessories designer Lulu Guinness keeps the home fires burning with cozy weekend parties in London.

Having whipped up a shepherd's pie with the greatest of ease last evening in the kitchen of her house near Notting Hill, the accessories designer Lulu Guinness is now working her culinary charms on the rest of today's very English luncheon.

"The main thing is to do all the big cooking beforehand, isn't it? Then you just have to heat it up when everyone arrives. And shepherd's pie is perfect: best when made the day before and left overnight in the refrigerator. The seasonings saturate the meat," says high-heeled Lulu, carefully fixing an apron over her Agnes B. skirt.

About eight friends and family, aged six and

upward-"Always mix ages at a party," Lulu says-are expected midday for hard-boiled quails' eggs with cayenne pepper, beets with orange zest, puree of carrots with nutmeg and creme fraIche, cheeses, cupcakes, and, of course, the aforementioned shepherd's pie made with ground lamb, tomatoes, carrots, finely chopped celery, rosemary, garlic, shallots, and small organic potatoes mashed with milk and amply buttered to alarm all sorts of international health organizations. (According to Lulu, a shepherd's pie is shepherd's pie only if it is made with lamb; it is called cottage pie when fashioned with beef.)

The company will include the younger of Lulu's two daughters, Madeleine-sister Tara is away at boarding school; Lulu's sister-in-law Camilla Guinness, a decorator; Hugo Wilson, a young portrait artist in the midst of sketching Lulu; and the illustrator Martin Welch, who recently did the drawings for Lulu's spirited style guide, Put on Your Pearls, Girls!, which Rizzoli will publish next month. Marx had his manifesto, so why shouldn't Lulu? Her unsinkable, feminine formula for personal and professional success states that there is very little in daily life that cannot be empowered with a lavish application of panache. Sotheby's will launch the book in New York with an exhibit of Lulu's collectible bags, from March 31 through April 2; Sotheby's special evening for Lulu on opening night will benefit the Children Affected by AIDS Foundation.

Lulu and her husband, Valentine Guinness, whom she met in the early eighties when she sang backup in his then rock band, Panic, bought this late-nineteenth-century house-a former bedsit or, as Americans say, boarding house-in 1989. (Alas, the Guinnesses recently ...