First off all peel onions and garlic.
Take a large pot and add in 2 cups of water.
Now add in peeled onions, garlic, tomatoes and green chilies.
Let the veggies boil for about 15-18 minutes on medium heat.
Now blend the boiled veggies in a blender or with the help of a hand blender.
Keep the blended veggies aside.
Now, make a spice paste.
Mix in all the spices in a bowl and add some water to make a paste.
Keep the spice paste aside.
Now take a pan, heat 6 tbsp avocado oil and fry the spice paste for 30 secs.
Now add in the blended veggies and carefully mix as it starts bubbling.
Cover and cook on low flame for a about 18-20 minutes while stirring occasionally.
Let the cooked sauce cool completely on room temperature.
Store the cooked sauce in air tight containers or sterilized glass jars.