Crumble with ice cream on the left: in the pan on the rightI’ll admit it; I thought Nigella Lawson made the best crumble topping until just about last week. But I have been wrong before (I turned my back on Paul Hollywood’s focaccia after trying a no-knead overnight recipe, and even learned to take Gordon Ramsay’s carrot cake advice with a grain of salt); and I was wrong again. Following my most recent Sunday roast, I thought I’d give Mary Berry’s crumble recipe a try.The dessert didn’t last 15 minutes; friend after family member scraped every last morsel from its inevitably too-small earthenware home.How does Mary Berry make her apple crumble?The former Great British Bake-Off&l