Peel the onion and cut into fine cubes along with the zucchini. Cut the lemongrass into pieces approx. 5 cm in size. Peel and finely chop the ginger.
Fry the zucchini with the onion cubes in hot oil until translucent. Then add the sugar, lemongrass, ginger, vinegar, salt and curry, put a lid on the saucepan and simmer until the vegetables are soft. Meanwhile, pluck the basil from the stems, wash, pat dry and finely chop. When the vegetables are done, remove the lemongrass and puree the mixture with the hand blender or in a blender. Gradually add approx. 100 ml of hot water so that the mass has a finer consistency.
Then you mix in the freshly chopped basil and the freshly ground chilli flakes, stir in both well and let the puree boil again briefly. Finally, you fill the ketchup in hot rinsed bottles (preferably from any barbecue sauce or something similar) and close them immediately.
The zucchini ketchup goes well with grilled food. Especially with fish and poultry, but also very good with rice dishes.