Cut out the stems of dry chillies. Soak it in hot water for 1 hour, or boil it for 15 minutes (cover the pan with a lid while boiling the chillies) until it becomes soft. (Note: If you don’t want spicy sauce, discard the seeds of half the chillies (discard the seeds of 8 chillies & keep 8 chillies intact).)
Boil water in a saucepan. Add roughly chopped onion and cook until it becomes tender. Transfer the onions to a plate.
Blanch the tomatoes in the same water. Put a cross mark on the bottom side of the tomato, then drop it in hot boiling water and cook for 3-4 minutes until the skin starts to separate from the tomatoes. Transfer to a plate and let them cool down. Peel off the skin and keep them aside.
Add soaked red chilli, garlic cloves, onion, and tomatoes to a blender. Blend it to a coarse paste.
Heat oil in a pan or kadhai on medium flame. Add finely chopped ginger, minced garlic and Kashmiri chilli powder. Sauté it for 1-2 minutes until the raw smell disappears.
Now add coarse chilli paste and mix it well. Cook it on low-medium flame.
Add the soy sauce, vinegar, sugar and salt. Mix it well.
Cook this chutney and keep stirring until it starts releasing oil from the sides. Check the seasoning and turn off the flame. (Notes: Add tempering of Kashmiri chilli powder to the chutney to make it spicier.)
Let it cool down completely. Store it in a glass container in the refrigerator for a longer shelf life.
Red Momo chutney is ready to serve with piping hot momos.