In a medium bowl, whisk the yogurt until it is completely smooth and free of lumps. Gradually pour in the 2 cups (480 ml) of water, whisking continuously to combine.
In a small, separate bowl, mix the chickpea flour with a tablespoon of water to form a smooth, lump-free paste.
Add this paste and the salt to the yogurt-water mixture and whisk thoroughly until everything is well incorporated.
Place a small saucepan or pot over medium heat and add the oil.
Once the oil is hot, add the asafetida and cumin seeds.
Let them sizzle for about 10-15 seconds until fragrant.
Add the split chili and the crushed garlic to the pan.
Stir for a few seconds, being careful not to let the garlic brown.
Immediately pour the yogurt mixture into the pot.
Stirring constantly, bring the karhi to a gentle simmer over low to medium heat.
Continue to simmer and stir for 2-3 minutes to cook the chickpea flour.
Serve hot.
Stir the karhi continuously on low heat as it comes to a simmer. This is the most crucial step to prevent the yogurt from splitting.
Don't let the garlic burn in the hot oil.
Sauté it for just a few seconds until fragrant before adding the yogurt mixture to avoid a bitter taste.