I substitute all the time. I always have non-fat Greek yogurt and have never bought sour cream. It does not like direct heat as in a saute pan. Turn off the burner heat and stir it in. It will stay creamy and even hold up if you transfer the pan to the broiler for a top toasting with a bit of breadcrumbs for the 5 minutes or so that takes. It is probably the high fat content of sour cream that keeps it from separating so quickly. I've never used sour cream so i don't know if it also will separate like milk does if keep at a high temp for too long.
Greek yogurt is thick, sometimes too thick, so i often will thin it in a jar with a bit of stock or sauce from my dish/soup, etc or a bit of water before stirring it in. If i need, or want, to cream up a soup or chowder, i will often put a bit of the soup with some of the veggies in the blender with some yogurt before adding back to the hot soup, but always at the end of the cooking.

This is information from The Cook's Thesaurus (link below):

Substitutes for one cup sour cream: Blend one cup cottage cheese plus two or three tablespoons milk or buttermilk plus two tablespoons lemon juice OR blend equal parts cottage cheese and plain yogurt OR blend one cup cottage cheese plus one-third of a cup buttermilk plus one tablespoon lemon juice. (Adapted from directions in the Joy of Cooking by Marion Rombauer Becker and Irma Rombauer. See my sources.) OR blend one cup cottage cheese plus two tablespoons lemon juice plus two tablespoons fat-free mayonnaise plus one-fourth cup nonfat buttermilk (adapted from a recipe in the New Laurel's Kitchen Cookbook) OR Combine 7/8 cup buttermilk or yogurt plus three tablespoons butter or margarine (From a Gateway Virginia recipe. See my sources.) OR one cup buttermilk OR one cup well-drained yogurt (if making cheesecake, use whole milk yogurt) OR one cup sour milk OR let stand for 5 minutes: one cup evaporated milk plus one tablespoon lemon juice or vinegar OR jocoque OR smetana (lower calories)

I use Fage 0% fat free Greek Yoghurt as a direct substitute for sour cream in everything, including on baked potatoes. I do not bake, so can't offer experience on baked goods. I also do not add it to very hot dishes directly on the stove top. I use the same method as sleevendog but, that's how I used to add sour cream when I used sour cream when cooking.
I actually brag about how healthy the dips and old stand by recipes/dishes are now since subbing the Fage 0%.

If I'm adding yoghurt to a hot dish, I stir one tablespoon of plain flour into the yoghurt first.

Thanks for all the info! I will try it again with all the tips.

Collenoz, I don't quite understand what you mean.

I agree, I add yogurt instead of sour cream nearly always, as I make my own yogurt and nearly always have some on hand, but seldom have sour cream.

I use it in baked goods in place of sour cream or buttermilk and get good results, but as has been mentioned, you can't boil it in stove top dishes, it separates instead of staying creamy.

I think Colleen means that she stirs a tablespoon of flour into the yogurt and then adds it to the dish, the flour helps stabilize the dairy.

Annie

Oh ok. It did have cornstarch in it. Like it said it was a new recipe but I did follow the directions. Maybe just need to move it off the heat when I add it. I didn't know you could sub yogurt for buttermilk. Great news as I usually skip buttermilk recipes!

Debra, you can also just take a cup of milk, add a tablespoon of vinegar or lemon juice to it and let it sit a few minutes, then use that in place of buttermilk in baking.

Annie

This post was edited by annie1992 on Fri, Jan 17, 14 at 21:19

Annie's got it in one :-)