Call it retro, call it vintage, whatever.  Nice slab of local beef fillet, (1.2kg) seasoned and roasted at 220C for 20 mins, then chilled and rested.  Mushroom duxelle of finely chopped chestnut mushrooms, fried in a little olive oil, added half a glass of white wine and reduced to dryness.  Fillet massaged with salt and pepper and English mustard.  Rolled out puff pastry base.  Laid out clingfilm, with double layer of prosciutto, then layer of duxelle in centre.  Laid fillet on to duxelle, then coated rest of fillet and rolled into tight sausage with the clingfilm.  Rested for a while, then removed clingfilm and laid wrapped fillet on to pastry base.  Rolled out pastry top, well oversize.  Painted joining faces with beaten egg, sealed, ensuring no trapped air, then  rolled over joint and pressed with spoon handle to seal.  Marked pastry with curved incisions from back of a knife, then coated liberally with egg.  Baked for 30 mins at 190C in fan oven until golden, checked temp withmeat thermometer, 52 degrees at the core for a reasonably pink finish.  Rested 10 mins then carved into thick tranches.  Served with crushed parsnips, chopped carrots with herb butter, mashed potato and sweet potato, creamed together with parsley, chopped brussels and chestnuts.  Meat gravy and a tart and glossy plum sauce to finish.