Make a fine paste of Jack fruit in a mixer grinder.
Melt jaggery and remove the impurities if any.
Take a heavy bottomed pan and add the jaggery and Jackfruit pulp. Keep stirring till they are nicely incorporated and becomes thicker.
When the mixture becomes thicker, add ghee at regular intervals and keep stirring in low flame till all the ghee are nicely incorporated with the jackfruit and jaggery mixture. When the mixture started to roll like a ball without sticking to the sides of the pan, add cardamom powder and mix well.
You can check the consistency of the chakka varatti by taking a small quantity of halwa in your wet hands and try to make a ball. If you are able to make a ball, then switch off the flame. Take the chakka varatti in a serving bowl.
You can preserve chakka varatti by keeping it in an airtight container.
Recipe by Kerala Cooking Recipes at https://www.keralacookingrecipes.com/chakka-varattiyathu-jackfruit-halwa-jackfruit-preserve/