What you need:
– Plum tomatoes
1. Wash the tomatoes and remove the seeds from them.
2. Cut into small pieces.
3. Set in a pot and boil on medium heat till very soft.
4. Pass the pieces of boiled tomatoes through a wire mesh sieve into another pot. Stir and press the tomatoes in the sieve with a wooden spatula.
5. After doing this for all the boiled tomatoes, you will have a smooth puree in the pot and the skin of the tomatoes in the sieve.
6. Set the pot of puree to boil till all the water dries up.