DUBLIN, Ireland - When it comes to classic British and Irish desserts, the proof is in the pudding - literally. Forget those smooth, gelatin-like convenience foods found in American supermarket snack packs and quick-mix aisles; these puddings are cakey, thick and rich. And they are a staple of the holidays. Reigning supreme among puddings are sticky toffee pudding (a spongy cake studded with dates and smothered in toffee sauce) and the seasonally ubiquitous Christmas pudding (a heavy, moist fruitcake topped with a liquor sauce). While Christmas pudding rarely appears outside the run-up to the winter holidays, sticky toffee pudding is a quintessentially British dessert that is a favorite throughout the year. 'It's the kind of pudding you make when you want to spoil people,' says food historian Sara Paston-Williams, who recently wrote the book 'Good Old-Fashioned Puddings' for Britain's National Trust. 'You've got a sweet base pudding, and then you put more sweetness on t