Pound the escalopes between 2 pieces of plastic wrap until very thin. Season with salt and pepper, and set aside. Melt the butter in a saute pan and gently fry the onion. Meanwhile, combine the ground pork, bread crumbs, parsley, and sage in a bowl and when the onion is soft, add it. Season the mixture well with salt and pepper. Fry a tiny piece of the mixture and taste to check the seasonings. Adjust as necessary. Divide the mixture among the escalopes. Wrap them into bundles and tie each one with 3 strings to secure. Wrap the bundles in plastic wrap and twist to shape into rounds, then remove the plastic.
Fry the lardons, and remove to a plate, leaving the fat behind. Now brown the turkey bundles well on all sides. Deglaze the pan with the Cognac and reduce to about 1 tablespoon. Add the stock, cooked bacon, and blanched Brussels sprouts. Cover, and simmer until tender, about 15 minutes. Add the chestnuts, turning the paupiettes over as you do so, and continue cooking, 5 to 7 minutes. Stick a metal skewer in and touch it to your lip to make sure the centre is completely cooked. The skewer should be very hot. Cook's Note: Serve with a squash or pumpkin puree.