Carefully sweat the curry powder in the oil. Be careful not to get too hot, otherwise the curry powder will quickly turn bitter. Add the cayenne pepper and / or chillies and stir well in a small saucepan. Now add the cola, (be careful, add slowly, it foams a little), let it boil down slightly and then add the orange juice. Let it simmer slightly while stirring constantly. Then slowly stir in the tomato ketchup and tomato paste. Mix everything very well and simmer gently for another 2-3 minutes. Season to taste with salt, pepper and possibly a little more curry powder. If you like, you can add chilli until the desired flavor / spiciness combination is achieved.
It tastes best when the fried sausage (if it is to be a curry sausage) is sprinkled with a little curry and paprika powder before the curry ketchup is on top.
The ketchup also goes very well with anything grilled.
The addition of sugar is not necessary as the cola and the orange juice bring enough sweetness with them.