Using a fork, mash all the six bananas and set it aside. And pulse the biscuits in a mixer jar or coffee grinder into a coarse paste.
Add the ground biscuits and the mashed banana together and mix it well.
Now heat a saucepan and add 2 tsps of ghee. Add the banana-biscuit mix, ¼ milk, and ⅛ tsp cardamom powder for flavor.
Mix well and cook over medium-low heat for 5 minutes. Keep stirring in between and do not leave the halwa unattended.
Check for sweetness and add sugar if needed. The bananas add sufficient sweetness so that it won't be necessary.
Add 1 more tsp ghee after 5 mins and cook again for 4 to 5 minutes over medium-low heat. When the mixture starts bubbling, turn off the heat. The overall cooking time is 10-12 minutes. The halwa will thicken as it cools.
Garnish it with nuts and serve warm or cold.
Video
Notes
Do not cook the bananas for too long. It might give a bitter taste.
If you are using good-day biscuits, then use 5 to 6 biscuits.
Add sugar only if needed.
I went with a minimal amount of ghee. You can use up to 2 tbsps for this recipe.