Sophie Dahl had her first brush with fame at the age of four, when grandfather Roald Dahl named the lead character in his beloved children's book The BFG after her. As an adult, she achieved fame of a different kind when she posed nude for an Yves Saint Laurent perfume campaign in 2000. Hailing from a family of writers and actors, it was only a matter of time before Dahl would turn to more literary pursuits. She's published four books to date - including the cookbook Miss Dahl's Voluptuous Delights - and has been a columnist for British Vogue since 2003. Now, combining her interest in food and writing, the tall blonde has made it onto the small screen, with her own cooking show. The Delicious Miss Dahl (right; BBC Lifestyle, Thursdays at 10pm) makes a convincing case for home-cooked meals being expressions of emotion. 'Cooking should be geared around mood: what am I going to make today, and what does it say about how I feel? And suddenly the process becomes magic, an adventure,' says the delicious one. If the first episode, themed around romance, is any indication, Dahl is highly watchable and has a gift for words. She strolls through old London bookshops and gardens, waxing poetic, then brings the inspiration home to whip up dishes to suit her mood. But Dahl also has a fair bit of cheek. As she prepares a meal in celebration of the first burst of romance, she explains why she chose scallops on the half shell: 'We don't want to scare the suitor, at least not at first. Oysters are sort of an open invitation to carnal knowledge; scallops are less obvious and more elegant.' And when working fresh chilli into the marinade to add heat: 'It's a bad idea to then scratch your nether regions, which did once happen to someone I know. His girlfriend then made the fatal mistake of pointing a garden hose at the area, which in the case of chilli makes it infinitely worse. 'So that romance didn't blossom.' This combination of feminine charm and naughtiness reminds us of another kitchen goddess, and Dahl appears ready to give Nigella Lawson more than a little healthy competition. Setting aside the sports car fetishism for a moment, Top Gear host Richard Hammond (the short, floppy-haired one) explores another side to speed in Richard Hammond's Invisible Worlds (BBC Knowledge; Wednesdays at 8.10pm). The three-part show provides a microview of the world in motion, with footage shot by high-speed, high-definition cameras shown in extreme slow motion. Using 'technology that makes never-before-seen realities visible', Hammond talks us through the slow-motion detonation of a quarry cliff, eerie high-altitude 'sprites' in the atmosphere, the surface fungi of horse poo and the strange reverse lighting that comes off electrical towers. It's mainly a case of style over substance, but it does deliver some breathtaking footage of the physical world that cannot be seen with the naked eye. Finally, television's favourite (and only) serial killer of serial killers, Dexter (Fox Crime; Saturdays at 11pm), reaches the ripe-old vintage of season six. After finding and losing his one true soulmate - a woman who shared his 'darkness' (or urge to kill) - last season, Dexter comes back renewed and more industrious than ever with his unique brand of vigilantism. It seems he's even broadened his MO to include first-time offenders: in the first episode, he tracks down a wife-killer at his high-school reunion. Dexter's already shaky 'moral' ground seems ready to crumble altogether with his new demonic lease on life - or death, as the case may be. Meanwhile, the political and personal games at the Miami Metro Police Department, where Dexter works with adopted sister Debra, heats up as blackmail, favouritism and a marriage proposal are set in motion. As usual, a bizarre death sets the department on a season-long hunt for 'the big one' - the most formidable serial killer of the year. This time, the killer has a penchant for quoting the Good Book - a religious psychopath, who would have thunk it? We're almost ready to give the show a rest, but not before checking out guest star Mos Def (a hip hop artist turned actor) as Brother Sam, a reformed addict who runs a body shop for ex-convicts.