1. Mix the sugar, vegetable oil and salt together in a non-stick pan. Cook the mixture over low heat, stirring all the while, until the sugar melts and the mixture caramelizes.
2. Add 1 clove of garlic and cayenne pepper. Cook for a few seconds. Then, carefully deglaze the pan by pouring the red wine vinegar into the pan. Stir constantly. (There may be some spattering when you add the vinegar, so step back a bit and use a long-handled spoon to stir!)
3. When the sugar mass is nearly dissolved, add the bing cherries and blueberries. Raise the heat to medium and cook to thicken a bit, about 4 minutes.
4. Refresh the sauce with the remaining 2 cloves of garlic. Stir briefly and set aside.
5. Serve with barbecued ribs, duck or chicken. In the winter, serve a similar sauce using other fruits in season, for a roast dinner.