Preheat the oven to 200°C (180°C fan, gas 6). Let the puff pastry thaw. Peel and slice the carrots.
Wash and quarter the apple, core and slice.
Peel and slice a shallot and the garlic.
Mix altogether in a roasting tin.
Pour in the wine and add the berries.
Place the meat in the marinade. Cover and leave to marinate for 24 hours. Turn halfway through.
Clean and dice the button mushrooms.
Peel and chop the second shallot.
Saute in a hot pan in 1 tbsp oil until softened. Add the mushrooms and cook until the liquid evaporates. Remove from the heat, mix in the parsley and season with salt and pepper.
Crush the pepper in the mortar and spread out on a plate. Remove the meat from the marinade, pat dry and brown all over in a hot pan in the remaining oil. Turn in the pepper to coat.
Unroll the puff pastry and spread the centre with some goose liver.
Spread over about a third of the mushrooms.
Place the meat on top and spread with the remaining goose liver. Place the remaining mushrooms on top and lightly press on all sides.
Brush the pastry edges with the beaten egg.
Fold the pastry over the meat and press the edges well to seal.
Brush with the remaining egg and bake in the oven for 45 minutes until golden brown. Remove from the oven, leave to stand for a few minutes, cut into slices and serve with red cabbage and berries.