Early yesterday morning Rustic Kitchen, Jim Cafarelli's Park Square restaurant, was already bustling with plates of food being sent out to happy diners. But the several dozen people gathered weren't just any patrons - they had already been through the makeshift hair and makeup department and were ready to begin filming a pilot episode of a TV cooking show "In the Kitchen With Alissa Bigelow." The eatery's in-house studio has been used for special demonstration dinners and to film a previous version of the show -with Bigelow as host - that ran on the Internet. Cafarelli got nibbles from national outlets, but that required a slicker and bigger show. (And that meant hiring a full crew to film three shows over the weekend.) Bigelow, a former actress who worked for NESN for two years, called upon her friend "House, MD" director Deran Sarafian to work as a consultant and co-producer for the pilot. "Alissa's a natural. She's the kind of presence in the kitchen people can relate to," said Sarafian, who signed on before the writers' strike was settled.