Preheat the oven to 200°C. In a small bowl, mix cinnamon, nutmeg, clove, salt & pepper to make a sweet spice mix.
Drizzle oil and rub spice mix over the venison.
Sear venison in a large frying pan until brown all over, about 3 minutes each side. Reserve the fry pan.
Place quartered red onion in a large roasting pan, drizzle with oil, then place venison racks on top. Cook in the oven for 25-30 minutes. To check if venison is cooked to medium rare, insert a metal skewer into the centre of the meat and hold for 5 seconds – it should come out warm. If not, return to the oven for a further 5 minutes.
Remove venison from the oven, cover with foil and rest for 20min.
Meanwhile, make blueberry sauce. In the reserved frypan used to sear venison, add a little more oil and fry finely chopped red onion for 2 minutes. Add rosemary sprig and cook for 1 minute. Pour in the pinot noir, add cinnamon stick and simmer until reduced by half. Mix cornflour and 2 tbsp of the stock in a small bowl. Add the rest of the beef stock, blueberry balsamic drizzle and cornflour mix to the fry pan and let simmer until the sauce has thickened a little. Add blueberries and heat through. Season with salt & pepper to taste.
Transfer venison racks and roasted red onions to a serving platter. Pour over blueberry sauce. Serve with blueberry chutney and glasses of pinot noir.