Marinade the ox cheeks in the wine, star anise, carrot, celery, onion and chicken stock overnight.
Heat the oven to 140C. Remove the cheeks from the marinade, pat dry, season then seal in hot olive oil in a frying pan over a high heat. Place the cheeks in a meat dish and cover with the marinade. Cover with foil and cook in the oven for 3-3½ hours or until soft.
Meanwhile cook the shallots. Slice and cook them very gently in the oil and butter to soften. Then turn up the heat and allow to turn golden brown.
When the ox cheeks are tender, remove from the oven, allow to cool slightly and gently pull apart using 2 forks. Mix the meat with the cooked golden shallots then pack into a Pyrex pudding bowl and refrigerate for 3-4 hours until set.
Cut a disc of puff pastry 2.5cm larger than the top of the Pyrex bowl. Tip the dome of set beef mix on top. Egg wash the edges then cover completely with a second sheet of puff. Using a fork, crimp the edges then place in the fridge for 30 mins. Score gently with a sharp knife, then coat in egg wash. Cook the pithivier on baking paper on a baking sheet for 30-40 mins at 180C until golden brown and hot all the way through.
For the gravy, sauté the mushrooms for 3 mins or so in hot butter. Tip out, deglaze the pan with the whisky (it may set alight – if this worries you, have a lid handy to slam on). Add the stock and reduce well. Finally add the mushrooms back in, heat through and serve.
Serve with green veg on warm plates. Drizzle with the gravy and dot the mushrooms around.