Cut the onion into thin wedges, halve the pointed pepper lengthways and cut across into thin strips. Season the chopped vegetables with a little salt and a pinch of sugar.
Heat a pan and fry the prepared vegetables in a little vegetable oil over medium heat. Reduce the heat, add the curry powder and lightly roast.
Bring the ajvar, tomato ketchup, sambal oelek and the water to the boil in a saucepan. Add the fried vegetables to the sauce and simmer over low heat. Season to taste with pepper, salt, curry powder and sambal oelek.
Serve the sauce with the currywurst and French fries.