Wash the brains under running cold water or in several changes of water, and remove any clots of blood, loose skin and fibres. Then soak in cold water for at least 1 hr., changing the water 2 or 3 times. Put the brains in a saucepan, cover with cold water, and add the sliced onions, sage, salt, lemon juice or vinegar. Add the peppercorns and bay leaf tied in muslin. Bring to the boil and simmer for about 10 min. or until firm. Remove the muslin bag and allow the mixture to cool. Chop the brains, add seasoning to taste and sufficient beaten egg to bind the ingredients. Stir well over a low heat until the mixture thickens. Then spread on a plate in the form of a large round cake and allow to cool. When cold divide into equal small portions and form each into a cake. Coat with egg and breadcrumbs and fry in hot fat until light golden brown. Drain well and serve on a hot dish garnished with parsley.