Melt 110g/4oz of the butter in a pan over a medium heat, then add the onion and fry until softened, but not coloured.
Add the garlic and chicken livers and fry the livers until golden-brown all over and cooked through. Add the brandy and mustard powder and season well with salt and freshly ground black pepper.
Place the liver mixture and 55g/2oz of the remaining butter into a food processor and blend until smooth. Season, to taste, with salt and freshly ground black pepper.
Transfer the pâté into a serving ramekin or small dish and decorate with a couple of cranberries and a bay leaf.
Melt the remaining 55g/2oz of butter in a clean pan. Skim off the froth and pour the butter over the pâté. Transfer to the fridge to chill, then serve from the ramekin when ready.
