Preheat an oven to 180C degrees. Place a large ovenproof saucepan on a high heat and add the vegetable oil.
Then add the diced pancetta to the saucepan and cook until crisp, approximately 3 minutes. Remove the browned pancetta from the pan and set aside.
Dust the venison in flour and salt, then add the meat to the saucepan and brown well on all sides. When browned remove the venison from the pan and set aside with the pancetta.
Reduce the heat to medium then into the same pan add the chopped onion and carrot, cook for 5 minutes until softened. Then add the garlic and tomato paste, cook for 2 minutes.
Stir back in the browned pancetta and venison then top with red wine, venison stock and pearl onions.
Bring the saucepan to a boil then cover with a lid and transfer to the oven for 2 hours.
While the bourguignon is cooking, prepare the mushrooms. Place a medium saute pan on a medium heat and add the butter.
Once the butter has melted add the mushrooms and cook for 4 minutes then remove from the heat. Pour the mushrooms into the saucepan of bourguignon and continue to cook for 30 minutes more.
Remove the venison bourguignon stew from the oven and garnish with fresh parsley, serve with mashed potatoes.