Heat your olive oil in an oven-safe Dutch oven over medium heat,
Add the venison and break up into small pieces with a wooden spoon. Sear, stirring frequently, until the meat begins to brown, about 3 minutes.
Add your onion, carrots, rosemary, and thyme. Cook for 7-8 minutes or until the veggies are browned and softened and the meat is cooked.
Turn the heat to low. Deglaze the pan with the red wine and cook for 2 minutes at a simmer.
Next, add the water and bouillon pastes. Stir to dissolve the paste into the mixture. This stuff is pretty salty, so hold off salting the stew until before baking.
Continue to cook at a simmer for 45 minutes.
After 45 minutes, mix the cornstarch and water to make a slurry. Pour it into the stew and stir, allowing it to thicken for about 5 minutes. Continue to stir occasionally.
Once the stew is thickened, boil your potatoes in water seasoned with 1 teaspoon of salt. Once tender, drain.
Mash the potatoes along with the garlic paste, mozzarella, butter, and black pepper.
Preheat the oven to 375 degrees F.
Remove the stew and the potatoes from the heat. Carefully add an even layer of potatoes over the stew, inside the same Dutch oven you cooked in, smoothing out the top.
Using a fork, draw vertical lines across the mashed potatoes. This gives a nice texture to the potatoes, as the top gets nicely crisp from the fork pattern.
Bake for 35-40 minutes or until the top is golden brown.
Remove from the oven and allow to sit for 5 minutes before serving.