Melt half the butter in a large frying pan over medium heat and cook the onion for 3 - 4 minutes until soft and transparent. Add the garlic and continue to cook for a further 2 minutes.
Check the chicken livers and remove any discoloured parts using a pair of scissors.
Add the livers to the frying pan and cook over quite a high heat for 5 – 6 minutes until they are brown in colour and fully cooked.
Season well with salt and pepper and add the mustard and brandy.
Process the pate in a blender until smooth. Add the remaining butter cut into small pieces and process again until creamy.
Press the paté into a serving dish or 4 small ramekins, smooth the surface and cover and leave in fridge until set and ready to use.
Serve with brown bread and some redcurrant jelly.