I am obsessive about tomato chutney recipes. I enjoy trying out numerous variations, playing with the amount of tomatoes, onions and chillies going in every time and trust me you can never go wrong with the chutney. The different tastes are always exciting and tasty however you jumble the ingredients! I have my granma's (amma's too) version of Tomato Chutney already posted here which is a 'semi preserve' type.
Thakkali Thokku or the Spicy Tomato Preserve is a stronger Tamil variation of tomato chutney in which onions are avoided completely and given a final touch of vendayappodi (methi or fenugreek powder) for the characteristic 'pickle flavour'.
So let me assure, you can be a little flexible with the ingredients for this one and the final dish will be heartwarming as always!
Thakkali Thokku
Yields enough to fill two 200ml cups
Ingredients:
Ripe red tomatoes- 750 grams
Tiny garlic cloves- 40 numbers. ( I used 'tharai poondu' or the country garlic which are tiny and slender. If you have normal cloves, use 20 no.s. Halve or quarter them lengthwise.)
[Use one-third quantity of garlic for grinding and the rest for seasoning]
Table salt-1 tsp
Oil- 1/2 cup ( let this be a 50:50 mixture of any oil you use for cooking and gingelly seed oil/nallennai
Mustard seeds- 1tsp
Fenugreek seeds- 2 fat pinches
Red chillies- 3-4 no.s broken into 3 pieces each
Red chilly powder- 1- 1 1/2 tsp
Hing / perungayappodi -1/4 tsp
Methi powder/ venthayappodi - 1/4 tsp (the methi seeds should be dry roasted well enough before powdering)
Method:

Wash and slice the tomatoes. They can be long, but slice them thin. Retain the juice that ooze out.
Throw in 10-12 pcs/pods of garlic pods and a tsp of salt. Combine gently and transfer to a colander placed on a wide bowl. Sundry for a few hours or at least a couple of hours under 'good' sun ( I had this out for 4 hours as there wasn't much sun and quite breezy ). Toss once every 30-45 minutes. The juice thus drips further more and get collected in the bowl below. Grind the pieces to a smooth paste. (Do not add the collected juice or water while grinding)
*I had about 1 cup of drained juice and 4 cups of pulp. This was reduced to 2 cups finally.*

Heat oil in a non-stick kadai. Splutter the mustard and brown the fenugreek seeds. Add the rest of garlic followed by the broken red chilly bits. Sauté for a few seconds and mix in the ground tomato pulp.

Bring the mixture to a boil and keep the flame low. Make sure the kadai is wide and deep enough so as to avoid splutters. Allow the saucy mix to thicken. Now pour the reserved juice and mix along. Simmer for a few more minutes. Add the chilly powder, hing and curry leaves. Thicken the mix further until the watery part has all evaporated an the oil starts separating on the sides.

Add fenugreek powder and salt (check and add) and mix along until the oil separates and bubbles on the sides. It's quite fine if at all you don't see the oil separating. You may always drizzle a little if it doesn't. Just make sure you had reduced the pulp to half with the consistency as in the picture below. It need not be too thick. It should be moist, oily, glossy and happy :)
Always use ripe red tomatoes. You may not need to use country tomatoes. I used Bangalore tomatoes and they were perfect! If your tomatoes are ripe and towards the sweeter side than sourness, you may add a bit of tamarind paste. Use very little for the tanginess. Do not avoid the final addition of fenugreek powder. It's a must for 'that' special flavour.
Drizzle a little oil if you find it too dry towards the final stages. I recommend you to add the required oil while seasoning itself as the paste would get sautéed well enough from the start.
Thakkali Thokku keeps well for a few weeks if refrigerated.I learnt this recipe from my ma-in-law's co-sister. She suggests to top the preserve with castor oil/vilakkennai which increases the shelf life considerably for those days we never had the luxury of refrigerators. She mentions how the tomatoes were ground in large amounts those days in our ancestral village home using "aattu kallu" to serve the large joint family!
The spicy tomato preserve goes well with just anything and this was packed for sister during my visit to Singapore last month :)