Greek Yogurt (Best Option)
1:1 (1/4 cup Greek yogurt per 1/4 cup sour cream)Greek yogurt works well because its thick texture and tangy flavor closely replicate sour cream, which helps retain moisture and adds a subtle acidity that enhances the meat's flavor. The protein content also aids in binding the meat mixture.
To ensure success, use plain, unsweetened Greek yogurt and avoid varieties with added flavors. If the yogurt is too thick, you can thin it slightly with a teaspoon of milk to match the consistency of sour cream.
Compared to sour cream, Greek yogurt may impart a slightly more pronounced tang and a firmer texture, but overall it maintains the moisture and tenderness expected in meatballs.