Soak the rabbit pieces in water for one hour to whiten the flesh.
Season rabbit with salt and pepper and brown in oil for 4 minutes.
Sauté shallots, carrots, and celery until onions are translucent.
Stir in stock, cider, bay leaf, rosemary, and mustard.
Simmer the rabbit in the liquid for 45 to 60 minutes until tender.
Transfer rabbit to a pie dish and thicken the stock with the butter and flour mixture.
Preheat your oven to 220°C.
Roll out a strip of pastry and line the edges of the dish.
Cover the pie with a pastry lid, seal the edges, and make steam slits.
Bake for 30 to 40 minutes until the crust is golden and crisp.