In a small sauce pan, melt the jaggery with the water and the cinnamon, ginger and cardamom. Allow this to simmer for 2-3 minutes until the spices get incorporated in the liquid. Remove and keep aside for a few minutes to let it cool slightly.
Mix the flour, baking soda, salt in a bowl using a whisk and keep aside.
Remove the spiced melted jaggery in a bowl. Add the softened butter, sugar and egg. Whisk this on high speed using a hand mixer, until the mixture is light and fluffy.
Add the dry ingredients to this and fold until combined into a soft dough.
If this is too sticky to handle, then refrigerate this dough for 15-20 minutes.
Preheat the oven at 190 C / 375 F. Line 2-3 baking trays with baking paper.
Spread the granulated sugar in a flat dish. Divide into 30 equal portions and roll into a smooth ball between your palms. Roll each portion in the sugar and place on prepared baking tray around 1.5" apart.
Bake for 12 minutes, rotating the trays midway for even baking, to get crisp cookies. For slightly chewier cookies, remove them in 10 minutes. Allow to cool on wire rack. Pack in airtight container.