Firstly, blanch the tomatoes in enough water. take well ripe tomatoes

Further cover and boil for 3 minutes or till the skin of tomatoes starts to separate

Cool down the tomatoes completely, and transfer to the blender.

Puree the tomatoes without adding any water

Using a filter, extract the tomato puree separating seeds and skin of tomatoes

Further, stir and mix well

Boil the mixture well.

Make sure to stir occasionally, to prevent from burning

Further continue to boil for 10 minutes

Add in ½ tsp chili powder, 3 tbsp sugar and salt to taste.

Keep stirring till the tomato puree thickens

Also cook the mixture till the water is evaporated completely, and turns thick.

And in 3 tbsp vinegar, as they act as preservative.

Mix well and check for seasoning

Transfer the tomato sauce or tomato ketchup once cooled completely.