To prevent majjiga pulusu from curdling, temper the spices in oil first, then add the diluted yogurt mixture and heat gently on low heat, stirring constantly until just warmed through. Do not boil.
The key to a smooth, non-curdled majjiga pulusu lies in controlling the temperature and acidity. Here's a step-by-step guide:
Prepare the Yogurt Mixture: Whisk yogurt (preferably slightly sour) with water to achieve a buttermilk-like consistency. The ratio is usually 1 part yogurt to 2-3 parts water, but adjust to your preference. Add gram flour (besan) to the yogurt mixture (about 1 tablespoon per cup of yogurt) and whisk well to prevent curdling. The gram flour acts as a stabilizer.
Temper the Spices: In a pan, heat oil (usually mustard or vegetable oil) over medium heat. Add mustard seeds, cumin seeds, and asafoetida (hing). Once the mustard seeds splutter, add chopped green chilies, ginger, and curry leaves. Sauté for a few seconds until fragrant.
Combine and Heat Gently: Reduce the heat to the lowest setting. Slowly pour the diluted yogurt mixture into the pan with the tempered spices, stirring constantly. Add salt and turmeric powder.
Heat Through, Do Not Boil: Continue stirring constantly. The goal is to gently warm the majjiga pulusu, not to cook it. Heating it too much will cause the yogurt to separate and curdle. Heat until you see steam rising and the mixture is just warmed through. This should take only a few minutes.
Garnish and Serve: Remove from heat immediately. Garnish with fresh coriander leaves. Serve chilled or at room temperature.
Always use fresh yogurt and avoid using yogurt that is overly sour, as it is more prone to curdling. If your yogurt is very sour, add a pinch of sugar to balance the acidity.