I've subbed soy based and full fat yogurts for sour cream in a lot of recipes and haven't had major problems w/ outcome. I've never made a kugel, but am guessing that the sour cream is used for flavor and richness, so it's a substitution I'd make, though as betteirene wrote above, try to use a full-fat version, not low fat.

I just substitued Greek yogurt for sour cream to dollop on spicy tacos that we made. You would not have known that it wasn't sour cream.

Honestly, it was just a thought that struck as I was standing in the store, stocking up on the 5 kinds of dairy needed for the kugel. Certainly, the recipe is in no need of improvement (and full-fat yogurt isn't exactly saving anything over the sour cream, anyway, though I do sometimes slip in low fat sour cream because, good lord, how much dairy fat is *really* necessary?).

Thanks for the advice!

I've substituted in things like stews, but wouldn't in something baked like this. I think sour cream will give you a better texture. Besides, sour cream is much lower in fat than most fresh cream. It's practically health food!

Just a question to your question: why would you want to replace it with greek yogurt? For health reasons? Sweet kugel is a timeless recipe I don't mess with. But good question!

I've never tried it in kugel, but I have substituted yogurt for sour cream plenty of times in baking and cooking and no one has noticed a difference. The trick when it will be cooked is to use full-fat Greek yogurt because low-fat yogurt tends to curdle when it's heated.

Yes, but isn't greek yogurt already thicker?

Yogurt and sour cream aren't completely interchangeable: yogurt has less fat than sour cream, and curdles at a lower temperature. It's also slightly less thick than sour cream, which can result in changes to the texture of whatever you're making. I think you could get away with swapping out half the sour cream for yogurt, if you mix the two together before adding to the other ingredients. You might also consider setting the yogurt in a cheesecloth-lined strainer set over a bowl, and letting it drain for a couple hours to remove some of the whey and help thicken it.