In a heavy based casserole dish heat the oil and cook the onions for around 8 minutes over a medium heat.
Add the garlic cloves and chilli and cook for a minute more.
Add the carrots and cook until just starting to soften.
Add the coriander, cumin, cinnamon and cayenne pepper, stir well and cook until fragrant, about a minute.
Add the venison and brown.
Add the chopped tomatoes, wine and stock.
Turn up the heat and bring to a simmer while stirring.
Pop into the oven at 140C for 2/12 to 3 hours.
Remove from the oven, stir in the chocolate and serve immediately with rice if you like.