What’s worth watching on food-TV this week? Martha Stewart’s all about Thanksgiving this week; she even has a hotline up T-Day emergencies (email thanksgivinghotline@marthastewart.com). Her mashed potatoes tip? Use buttermilk instead of heavy cream or cream cheese—“Delicious,” she says. On Monday, she’s making sides and teaching people about heritage birds and how to find the perfect turkey. On Wednesday, she’ll be answering people’s last minute holiday questions—sent in via the hotline--throughout the show (Monday-Wednesday, Friday,......