Melt a large knob of the butter in a large frying pan and cook the chicken livers for 3-4 minutes on each side until well browned but still slightly pink in the centre.
Place in a food processor and whizz until smooth. Remove the pan from the heat, add the brandy and swirl around to gather up the pan juices. Add to the food processor with the garlic, tarragon and the remaining butter and whizz again until well blended.
Add some salt and pepper followed by the cream and process again until well mixed. Spoon into 6 ramekins, smoothing the surface level, and leave to cool completely.
To finish off, melt the butter and pour over the surface of the pate. Drop in a few tarragon leaves as decoration.
Cover with cling film and chill for at least a few hours, but up to a day or two. Serve straight from the fridge with hot, buttered toast, or melba toast if you're feeling posh.