Take red tomatoes and roughly chop all the tomatoes.
Now take muslin cloth and put cloves, cinnamon stick, roughly chopped onion, garlic and ginger, tie a knot and make potli out of it.
Take a deep pan and put chopped tomatoes, spice potli and cook on medium flame for 10-15 minutes or till the tomatoes become soft by covering the lid. Do stir after 10 minutes.
Once cooked, keep aside to cool down.
Before grinding tomatoes take out the potli from the mixture and squeeze to extract all the flavours.
Now put cooked tomatoes into the jar and grind it to make puree.
Strain the mixture through a strainer to make smooth puree
Put tomato puree in a pan, add red chilly powder, salt, sugar, vinegar and cook till sauce becomes thick or 1/3 of its original quantity.
To check the right thickness of sauce take a teaspoon of sauce on a plate and if the water does not separate it means the sauce is ready and if there is water content then cook it for some more time.
Keep sauce cool down for some time.
Take 1 tsp of hot water and dissolve sodium benzoate.