1) Preheat oven to 180 °C. 2) Heat the oil in a small sauté pan and gently cook the Onion with a pinch of salt until very soft. Set aside to cool. 3) Place all the ingredients including the cooled Onion in a large bowl, and mix until well combined. 4) Line a terrine or other deep, oven proof dish with the Bacon, allowing the excess to hang over the sides. Pack the mixture into the dish and fold the Bacon over the top to cover the terrine completely. Place the lid on top or cover well with a double thickness of tin foil.