Pour the milk into a heavy-bottomed saucepan and bring it to a gentle boil over low to medium heat, stirring occasionally to prevent it from sticking to the base. Allow it to simmer until it slightly thickens and reduces in volume.

Add saffron strands, cardamom powder, and the chopped nuts to the milk. Continue to simmer for a few minutes until the saffron releases its color and aroma, infusing the milk with a delicate golden hue.

In a separate bowl, place the mashed banana. Gradually pour the warm, flavored milk over the banana while stirring continuously to blend everything into a smooth, creamy mixture. Adjust sweetness with jaggery powder according to your taste, mixing until it fully dissolves.

Pour the Banana Kheer into serving bowls and let it cool slightly. Garnish with fresh banana slices and a sprinkle of chopped nuts before serving. It can be enjoyed warm or chilled for a refreshing twist.