Heat the oil to a medium heat in a saucepan.
Add the onion & garlic and fry for around 5 minutes.
Stir in the ginger, curry powder, turmeric, five spice, cider vinegar and raisins and cook for 3 minutes.
Add the stock, lemon juice and soy sauce and simmer for 20 minutes.
Blitz everything in a blender or using a hand blender until smooth.
Add the cornflour slurry and stir for 2 more minutes until the sauce has thickened. If it is not thick enough, add more slurry.
Add salt to taste.