In a frying pan over a medium heat, melt the butter then add the mustard powder, onion and garlic. Cook and stir for 5 minutes until soft. Add the chicken livers and cook until browned, but still pink in the centre. Add the brandy, lemon juice, cream and parsley and season well. Remove from the heat and blend until smooth in a food processor.
Spoon into 6 ramekin dishes and smooth the top. Chill in the fridge for 2 hours until set.