Steam the Tomatoes & Coriander Roots: In a deep pot, combine the quartered tomatoes, sliced ginger, cleaned coriander stems and roots with a 1/2 cup water. Cover and cook on medium heat. Simmer until the tomatoes are completely mushy, and the ginger and roots have infused their deep aromas into the liquid.

Dry Roast the Cumin: While the tomatoes are simmering, heat a small pan on low heat. Add the whole cumin seeds and dry roast them for 1–2 minutes until fragrant. Remove the tomato skin immediately and let them cool down.

Blend into a Smooth Base: Allow the cooked tomato, ginger, herb, and pepper mixture to cool completely. Strain out the excess water. This water is a nice stock for aromatic texture for pure veg curries.

Transfer everything (including the softened coriander roots/stems and ginger) into a clean mixer-grinder. Blend on high speed until it forms a perfectly smooth paste.

Strain for that Sieve-Smooth Texture: Pour the blended paste through a fine-mesh sieve directly into a bowl. Use a ladle or spatula to press the pulp through. This step is crucial because it filters out all the fibrous bits from the coriander roots and other residues, leaving you with a silk-smooth commercial ketchup texture.

Set the Rice Cooker on the Warm Mode: Heat 1 tsp of pure cow ghee or butter and sprinkle the grounded resin hing. Allow the hing to sizzle and release its intense aroma for a few seconds. Pour in the strained tomato puree.

Preservation and Storage: Stir in the fresh lemon juice after removing the ketchup from heat. Let it cool completely at room temperature and bottle it.