First remove the seeds of custard apple and separate the all pulp and mash it with the hand. Keep aside.

Now wash the gobindo bhog rice nicely and soak with water for 30 minutes. Then strain water and spread it on tissue paper to little dry up. Take a grinder jar add soaked rice and coarsely grind it. Keep aside.

Transfer the milk into a heavy kadai on medium heat and wait for it to come to a boil. After that reduce the milk for about 8-10 minutes. Stair regularly so that the milk doesn't catch the bottom or side of the kadai. Now add soaked and grind rice and cooking on low heat until the rire is fully cooked and becomes thickens.

Now add sugar and cardamom powder mix it properly and cook another 2-3 minutes.

Now turn off the flame and cool down little and add mashed custard apple mix it well. Keep aside for cool down to room temperature. Then keep it in the fridge to cooling.

Custard apple firni is ready to serve.