Wash the tomatoes properly, make 2 cuts (horizontal and vertical) on it. Insert fork on the other side of the tomatoes and directly roast on medium flame till it changes colour and skin turns black.

Let it cool down to room temperature and gently remove the skin. Roughly crush the tomatoes and blend it to smooth puree using mixer grinder. Strain the puree if there are seeds in it.

Heat butter in a pan on medium flame and add carrom seeds. Add strained tomato puree. Then add salt, sugar and water. Mix well and cook for 8 to 10 mins till it thickens. Switch off the flame.