Wash the chillies, quarter them lengthways and cut them into small pieces together with the seeds. Peel the ginger and garlic and chop very finely.
Put the sugar in a saucepan and moisten with a little water. Melt over medium heat. Sauté the garlic and chiles in it for about 5 minutes. Take the pot off the stove and let it cool down briefly. Add the ginger, pour in 1/4 l water and bring to the boil while stirring. Mix the cornstarch with a little cold water, pour the vinegar into the syrup and let everything boil gently for about 3 minutes. Salt and let cool.
Tip: The sauce goes very well with poultry. You can marinate the meat with it before grilling and use the sauce as a dip.