Originally from https://honest-food.net/slow-cooked-deer-shoulder-recipe/

FOR THE POT
* 1 large onion, sliced thinly root to tip
* 1 head garlic, cloves peeled but whole
* 2 teaspoons dried thyme
* 1 1/2 cups broth or stock, any kind
FOR THE DEER SHOULDER
* 1 deer shoulder
* 4 cloves garlic, cut into little batons
* 3 tablespoons melted palm oil or peanut oil
* Salt
* 3 tablespoons Dijon mustard
* 3 tablespoons ground cumin
* 2 tablespoons freshly ground black pepper, or selim pepper
TAMARIND KANI SAUCE
* 1 tablespoon peanut oil
* 1 small onion, chopped
* 2 cloves garlic, chopped
* 6 plum or paste tomatoes, chopped
* 1 or 2 habanero or Scotch bonnet peppers, chopped
* 1 bay leaf, crumbled
* 3 tablespoons tamarind paste, seeds removed (some brands still have seeds in them)
* 1 tablespoon sugar (optional)
* 2 to 3 tablespoons Vietnamese or Thai fish sauce
* Salt and black pepper to taste

Instructions

PREPPING THE ROASTING PAN
Line a roasting pan with lots of foil, overlapping so it’s reasonably watertight. You will need to completely wrap the deer shoulder, so have enough foil to do that.
Scatter the sliced onion and garlic cloves in the pan, then sprinkle with the thyme. Pour in the stock.

PREPPING THE POT ROAST
Using a thin knife, stab the venison in various places and shove the batons of garlic inside. Coat the whole deer shoulder with the oil. Salt it well. Mix the mustard, cumin and black pepper together and smear this all over the deer shoulder, getting it into every crevice.
Seal up the shoulder and set in a 200F oven. Roast until tender, which should take at least 3 hours, and as many as 10. With normal deer, start checking after about 5 hours. You want the meat to lift off the bone easily.

TAMARIND KANI SAUCE
If you’re making the sauce, do this while the venison cooks. Heat the peanut oil in a large pan over medium-high heat. Cook the chopped onion until translucent, but not browned, about 5 to 8 minutes, stirring often. Add the garlic and chopped habanero chiles and cook another minute.
Add the remaining sauce ingredients, mix well and simmer for about 15 minutes. Turn off the heat and puree in a blender. The sauce should be thick like ketchup.

TO SERVE
To serve, give everyone some deer shoulder with some of the juices from the pot, stewed onions and garlic, and serve with the tamarind kani sauce on the side. Crusty bread, rice or sweet potato-plantain fritters are a good accompaniment.