This recipe is a variation of the baked rice with mussels and potatoes dish that is a traditional in the region of Puglia. The secret of this dish is the slow cooking and resting the dish for 4 or 5 hours before serving so the flavours really develop. It will smell so good you will want to serve right away, but try and wait! In fact, you can prepare this dish in the morning for that evening or the day before and store in fridge. Pop it in the oven for 10-15 minutes and then grill the top to crisp up the breadcrumbs.