Soak the kashmiri dry chillies and dry red chillies in warm water for 2-3 hrs, if you don't want it too spicy, you can deseed both the red chilies or reduce the amount of red chilies.
Now grind these soaked red chilies, garlic cloves, ginger, cardamom, cinnamon, cumin seeds and 3-4 tbsp vinegar into a fine paste. Marinate the chicken with this paste for 45 mins -1 hour.
Heat a kadai with 3-4 tbsp oil, add the thinly slice onions and fry till it turns brown in colour. Then add the marinated chicken and fry the chicken on a high flame for 4-5 mins. Now add in turmeric,coriander powder, salt and give it a good stir.
Then reduce the gas on a low flame, cover and cook for 15-20 mins while occasionally stirring the chicken in between.
After 20 mins, once the chicken becomes tender and the masala separates from the oil, means it's almost done.
Now you can add water as per your desired consistency and keep cooking it further for 5-6 mins. If you want it to be a little more tangy, you can add a little more vinegar at this time. Next, add the garam masala and check the seasoning.
Chicken vinlaoo Is ready to be served! Serve it with steam rice/ bread / roti or whatever you like to eat.