At work, we have the birthday cake thing. If it's your birthday, you bring a cake. Or someone else brings one. Whichever. As long as there is cake. My good friend turned 30 at the weekend - although I don't think she is ready to embrace her thirties just yet - and her favourite cake, we discovered by gentle probing and MI5-style questioning, is Erdbeerkuchen. Now you may think, hmm, a cake with beer? But no, die Erdbeere is the German for strawberry, and der Kuchen is, of course, cake. The beauty of this cake is the simplicity, and the freshness, and, I expect, the nostalgic feeling brought about by eating something from your childhood.