Sour Cream (Best Option)
1:1 (1 cup sour cream per 1 cup Greek yogurt)Sour cream works well because it has a comparable fat content and acidity level to Greek yogurt, which helps preserve the moisture and tangy flavor in Shepherd's Pie. The lactic acid bacteria present in sour cream provide a similar flavor profile, enhancing the savory components of the dish.
For best results, use full-fat sour cream and avoid low-fat versions to maintain the creamy texture. Stir gently into the filling or topping to avoid curdling during baking.
The final dish will be very close in taste and texture to using Greek yogurt, with a slightly richer and less tart finish, which many find equally satisfying.