Cut the turkey breast into small cubes and mix in a bowl with 4 tablespoons of soy sauce, lemon juice and 2 tablespoons of oil. Peel garlic, press through a garlic press and add.
Peel and finely chop the ginger. Cut the chillies lengthwise, remove the seeds and cut the pods into fine rings. Mix the ginger and chillies into the meat, cover and leave to stand in a cool place for at least 1 hour (or overnight if desired).
Clean, wash and cut leek and carrots into fine strips. Wash chives, dab dry and cut into fine rolls. For the dumplings, stir the contents of the packet into 1/2 litre of cold water with a whisk and leave to swell for 5 minutes.
Then form about 24 small dumplings from the potato dough with moistened hands. Place the dumplings in plenty of boiling salted water and let them simmer at low heat for about 10 minutes (no longer boiling).
In the meantime, heat the remaining oil in a pan and fry the meat in 2 portions. Finally add vegetables, braise briefly and deglaze with chicken stock. Add ketchup and simmer for about 2 minutes.
Add the sauce thickener while stirring and bring to the boil again briefly. Season to taste with the remaining soy sauce and possibly a little salt. Drain dumplings well and arrange on plates with the goulash. Sprinkle with chives and serve garnished with coriander leaves as desired.