Greek Yogurt (Best Option)
1/4 cup Greek yogurt per 1/4 cup sour creamGreek yogurt works well because it has a similar creamy texture and tangy flavor due to its fermentation process, closely mimicking sour cream's acidity and mouthfeel. The protein content helps maintain creaminess when mixed into curry.
To avoid curdling, add Greek yogurt towards the end of cooking and temper it by mixing with a small amount of hot curry liquid before combining fully. Stir gently and avoid boiling after adding.
The final curry will have a slightly thicker texture and a fresh tang similar to sour cream, enhancing the spices without overpowering them.