Sprinkle venison leaf with brandy and rest for 10 min. Preheat the oven (180 degrees). Season the venison with juniper berries, pepper, thyme and salt. Heat the fat in a roasting pan and brown the meat on both sides. Extinguish the roast with a little clear soup in between.
Towards the end of the roasting add the onion. Add the rest of the game stock and cook on the lowest rack in the oven for 80 to 90 minutes with the lid closed. Wrap the roast in aluminum foil and set aside.
Pour whipping cream to the stock, cook to a creamy sauce. Pour sauce through a sieve.
Score chestnuts crosswise on both sides (best with a cheese knife), place on a baking tray and roast in the oven (top rack) for 12 to 15 minutes. Peel chestnuts and set aside.
In a saucepan, heat butter, add chestnuts and stir through, sprinkling with sugar in between. When sugar browns, fish out chestnuts with slotted spoon, set aside.
Add whipping cream to saucepan form, stirring throughout to caramelize. Add chestnuts to whipped cream-sugar syrup mold and mix through.
By the way, did you know that clarified butter is obtained by extracting water, milk protein and lactose from butter?