I found this recipe in an Italian cookbook that my dad got a long time ago. It is delicious and looks like a lot of work, but is very easy to make! If you find the sauce too acidic or want it to be thicker, add some corn starch dissolved in water at towards the end and cook for a few minutes longer. If you have any leftovers, it tastes even better the next day. Preparation time does not include time to marinate.