1. In a large pot, fry the onions and garlic in the oil until the onions have softened. Add the chicken livers and cook until they're browned, then remove and set aside.
2. Add the mushrooms, bay leaf, tomatoes, water, peri-peri sauce, paprika and 30ml (2T) of the sherry and stir. Crumble the stock cube into the mixture, season with salt and pepper and simmer for approximately 10 minutes, stirring occasionally.
3. Remove from the heat, return the livers to the pot and stir in the balsamic vinegar and the balance of the sherry. Set aside to allow the flavours to develop.