In large skillet melt the butter, add the onions and garlic. Fry until they begin to brown, add the liver and continue to fry for 8-12 minutes until the livers are no longer showing any pink. Put the ingredients into blender/food processor and chop until the ,ixture is very fine and smooth. Grease a casserole dish and turn out the liver mixture into it. Preheat the oven to 180ºC . Bake the mixture for 45 minutes. remove from and allow to cool for 15 minutes then cover and refrigerate for 4-6 hours before serving.