Melt the bacon drippings in a large saucepan over medium-high heat. Sear the venison in two batches until nicely browned and remove.
Stir in the shiitake, onions and garlic; cook until softened; 1 to 2 minutes.
Add the cognac, wine and beef stock cube then simmer for 30 seconds to remove the alcohol flavour and dissolve the bouillon.
Stir in the venison, pepper, thyme, rosemary and bay leaves.
Bring to a boil then reduce heat to low and simmer gently until the venison is tender; about 2 hours or more; adding water as needed.
If using baby carrots add them during the last half hour of cooking. When the venison is tender you may wish to thicken the sauce by dissolving the cornflour in 2 tablespoons of water and stirring it into the sauce.