Place the 4 tbsp (0. 88 oz / 25g) of sifted chickpea flour into a 1-quart (1-liter) mixing bowl. Slowly pour in 0. 25 cups (2. 0 fl oz / 60ml) of the water, whisking vigorously with a fork or small whisk until it forms a perfectly smooth, lump-free paste. Gradually add the remaining 1. 75 cups (14. 2 fl oz / 420ml) of water along with the 2 cups (16. 9 oz / 480g) of smoothed plain yogurt, whisking continuously until the entire liquid base is thoroughly blended.
Pour the blended yogurt and chickpea flour mixture into a heavy-bottomed 2-quart (2-liter) saucepan. Directly into the pot, add the 0. 25 tsp (0. 03 oz / 1g) fenugreek seeds, 0. 5 tsp (0. 07 oz / 2g) cumin seeds, the 0. 5-inch cinnamon stick, the 1 cup (4. 0 oz / 115g) pressed shredded radishes, 0. 5 tbsp (0. 25 oz / 7g) sugar, 1 tsp (0. 2 oz / 5g) salt, and the 6-8 curry leaves.
Place the saucepan over high heat and stir the mixture constantly to prevent the yogurt from splitting until it reaches a rolling boil.
Once boiling, immediately reduce the heat to low. Allow the Mooli Karhi to simmer gently, stirring every few minutes, for 12 to 15 minutes.
Once cooked, remove the saucepan from the heat and cover it with a lid to keep warm.
Place a small frying pan or tempering pot (tadka pan) over moderate heat.
Add the 1 tsp (0. 2 oz / 5g) black mustard seeds and dry-roast them for exactly 0. 5 minutes.
Once the pan is hot, add the 2 tbsp (1. 0 oz / 28g) of ghee or butter, the dried red chili pod, and the 0. 5 tbsp (0. 25 oz / 7g) minced ginger root.
Fry these aromatics until the butter froths significantly or the mustard seeds turn a grayish color, crackle, and pop. Carefully pour these hot, infused seasonings directly into the resting Mooli Karhi and immediately cover the pot again with the lid. Allow the spices to permeate the curry for 3 to 4 minutes.
Finish by gently stirring in the 3 tbsp (0. 1 oz / 3g) chopped fresh coriander just before serving alongside hot rice.
Squeeze the Radishes Thoroughly: White radishes retain a significant amount of water. Pressing them dry ensures that they don't water down your curry and dilute the perfectly balanced sweet and sour flavors.
Do Not Stop Stirring: The most critical step in making any karhi is to stir continuously on high heat until the mixture comes to a full boil. This stabilizes the chickpea flour (besan) and yogurt emulsion.