In a bowl, beat egg with cream. Add salt and pepper and mix well. Add 100g of the livers, stir and chill for 30 minutes in the fridge.
In a small bowl, soak stale bread in milk.
Heat oil in a pan over medium heat: add onions and fry until golden. Add 300g chicken livers, salt and pepper; fry until livers are no longer raw. Transfer to a bowl and set aside to cool.
Preheat oven to 180 C / Gas 4. Line a 15x30cm loaf tin with baking parchment.
Combine egg/cream mixture, soaked bread and cooled livers; process the mixture through a meat grinder using the small-holes plate or pulse in a food processor until well mixed. Season with marjoram and nutmeg; stir in pistachios.
Transfer mixture into prepared loaf tin. Bake for 45-50 minutes.
Turn out of tin and allow to cool before storing in the fridge.