Clean the meat by removing any excess fat, then cut it first into strips about 3–4 cm wide and then into fairly large bite-sized pieces.
Heat a drizzle of olive oil in a large pot and sear the meat over medium-high heat until it’s beautifully browned on all sides. Once it’s nicely caramelized and the juices are locked in, remove the meat from the pot and set it aside.
In the same pan, sauté finely chopped celery, carrot, and onion for a few minutes, stirring frequently.
Add the sprig of rosemary and the whole garlic clove, letting them infuse their flavor.
Add the tomato paste and stir well to evenly combine it with the soffritto.
Return the meat to the pot and stir to combine everything well.
Pour in the red wine, allowing the alcohol to evaporate completely.
Pour in the broth, season with salt and pepper, cover with a lid, and cook over low heat for at least 2½ hours, stirring occasionally. The meat should be tender and juicy by the end.
Meanwhile, cook the potatoes, cut into chunks, in plenty of salted boiling water until tender, about 20 minutes.
Drain the potatoes and mash them directly into a pot using a potato masher.
Add the butter, milk, and nutmeg
Place the pot back over the heat and stir over low heat until you get a smooth, creamy mash.
Once the meat is ready, spread a generous layer of mashed potatoes on the bottom of each plate and place the meat pieces on top, well coated with their cooking juices.
Finish with a few sprigs of fresh rosemary for garnish and serve the venison pot roast immediately.
