Cut the onions into fine cubes. Fry the prepared turkey breast in oil on all sides. Steam the onion cubes. Pour in the stock and wine and cook the turkey breast for 30 minutes.
Remove the meat, cut into slices and cover and keep warm.
Add the vinegar, sugar, cloves, cinnamon and mustard to the stew liquid, season with salt, pepper and cayenne pepper. Stir in tomato ketchup, cook for 10 minutes.
Thicken the sauce with mixed cornstarch. Season again and let the sliced turkey breast soak in the sauce for another 15 minutes.