Rinse chicken livers under cold running water and drain, before patting dry with a paper towel.
Melt butter in a fry pan over medium-high heat until it begins to foam. Add livers (do this in two batches if necessary), and cook for five minutes or so, until lightly browned on the outside and pink in the centre before removing from the pan.
Add mushrooms and shallots and sauté for another three minutes. Add bacon and continue to cook until mushrooms and shallots have browned and softened. Sprinkle over thyme and bay leaves and stir through. Add cooked livers back in.
Pour over brandy and simmer for a minute or so, until most of the liquid is evaporated. Remove pan from the heat and set aside to cool slightly.
Place liver mixture into a food processor or blender and blend until smooth, scraping down the sides if necessary. Pour in cream slowly as it blends. Taste and season with salt. Run pâté through a sieve to remove any large lumps. Add in green peppercorns and stir through gently to disperse.
Divide pâté among smaller dishes (or one large dish) and smooth the surface. Cover and place into the fridge to chill.