Greek Yogurt (Best Option)
1:1 (1 cup Greek yogurt per 1 cup sour cream)Greek yogurt works well because it has a similar fat content and acidity level as sour cream, which helps in tenderizing the gluten and activating baking soda or powder for leavening. The proteins in Greek yogurt also contribute to a moist crumb.
For best results, use full-fat plain Greek yogurt and avoid flavored varieties. Stir it well before measuring to ensure even consistency. If the yogurt is too thick, you can thin it slightly with a teaspoon of milk.
Compared to sour cream, Greek yogurt produces a slightly tangier flavor but does not significantly alter the cake’s texture or rise, making it an excellent direct substitute.