Start by scoring an 'X' on the bottom of the ripe tomatoes using a sharp knife. Blanch them in boiling water for 45-60 seconds until the skins start to peel back. Quickly transfer the tomatoes to a bowl of ice water to halt the cooking process. Once cooled, remove the skins and roughly chop the tomatoes.

In a large mixing bowl, combine the chopped tomatoes, diced onions, and fine salt. Cover the bowl with a lid or plastic wrap and let it rest in the refrigerator overnight.

Drain any excess liquid from the vegetable mixture and transfer it to a large pot. Add the crushed garlic cloves and cider vinegar. Set the stove to medium heat and let the mixture simmer gently for 20 minutes.

In a dry skillet over medium heat, toast cumin, coriander, celery, and black mustard seeds for about 30-60 seconds until fragrant. Lightly crush the seeds to release their essential oils.

Add the toasted spice mixture, along with paprika and crushed black pepper, into the simmering pot. Stir well to dissolve the spices evenly throughout the chutney base.

Introduce the golden granulated sugar to the pot, stirring until it fully dissolves. Let the chutney simmer for 30-40 minutes, stirring occasionally.

If the chutney seems too loose, mix cornflour with a little water to create a slurry and stir it into the pot. Let it simmer for an additional 5 minutes.

Pour the hot chutney into sterilized jars while hot, filling them to the brim to preserve freshness. Seal each jar tightly and allow them to cool completely at room temperature.