In a large mixing bowl, combine the sifted ragi flour, sugar, and cardamom powder. Mix well to evenly distribute the dry ingredients.
Add the melted butter to the dry mixture, and combine using a spoon or your fingers until the mixture resembles coarse crumbs.
Gradually add water, a tablespoon at a time, mixing until a firm dough forms that holds together when pressed.
Preheat the oven to 180°C (356°F). Line a baking sheet with parchment paper. On a floured surface, roll out the dough to about 1/4 inch thickness.
Use a cookie cutter or a glass to cut out circular shapes from the rolled dough. Place these onto the prepared baking sheet.
Bake in the preheated oven for 12-15 minutes until the edges are golden brown and the cookies feel firm to the touch. Remove from oven and let cool for a few minutes before transferring to a wire rack.