How can I make carrot cake more fruity and fresh?
Culinary Artistry by Andrew Dornenburg and Karen Page has a large section on food pairings. For carrots they mention orange, ginger, lemon, basil and mint. I think any of these could work well, if done right. My suggestion would be first to use really good, flavorful carrots—preferably from a farmer's market. Second, I would tone down or even leave out some of the usual carrot cake spices so that you don't cover up the carrot flavor or the subtle flavors of your possible additions. Maybe fresh or candied ginger in the cake itself would be good. Orange or lemon curd and/or zest would work particulary well in offsetting the cream cheese icing. I'm thinking basil and mint might be better saved for another dessert.