I bought two fantastic chocolate moulds in Venice - rose shapes and leaf shapes. No baking involved, but I thought I'd include my first batch to show you how easy it is.
Just melt dark and white chocolate. Filled the moulds halfway then added a toasted hazelnut or pistachio, and topped with more chocolate. For the leaves I mixed in chopped pistachios and dried cranberries.
Lately I've also made some batches of Annabel Langbein's espresso hazelnut chocolate ripple  - pouring dark and white chocolate over toasted hazelnuts and mixing into a marble pattern using a skewer or knife. Add espresso grounds to the dark choc if you like. Do it in a tray and refrigerate until set. Cut into pieces. Whittaker's dark choc works really well. You can add dried fruit too for a bit of tang, and any other nuts you like.