How to make chocolate, hazelnut and prune cake Save Follow The juiciness and sweetness of prunes makes them a great match for good chocolate and hazelnuts, and you can take this cake to the next level once youâve made it for the first time: try steeping the prunes in armagnac for a week, rather than briefly in hot water. Put them in a jar submerged in the armagnac and strain off the alcohol when ready. The boozy prunes are great served with other desserts such as rice pudding, or in place of fruit in a Bakewell tart. I do this with both prunes and raisins in dark rum, too â a habit I picked up from my days working at St John restaurant. If you donât fancy booze, try using Earl Grey or rooibos tea bags with a little lemon peel.