Cake – What can replace vegetable butter

I guess it depends on what the substitution is for.

Certainly if the butter is just for flavour, it's a reasonable substitute (I think I'd use slightly more yogurt). But 9 times out of 10, fat is the main reason the recipe is calling for butter! Yogurt cannot substitute for a fat (butter) because it has very little fat.

If you lower the fat content of a baked good then you'll generally end up with a product much denser and less flakey. So if you feel you must do this for some reason, then I would increase the sugar in the recipe to compensate (sugar inhibits gluten formation and will help to make the result less chewy).

The other thing you'd better keep in mind is that yogurt is naturally sour and will become even sourer when baked at a high temperature. The longer you bake, the more sour it will become, so you might need to amp up the sugar significantly to maintain the proper flavour.

So for the most part, no, yogurt is really not a substitute for butter or any other fat. Obviously this is partly a matter of personal taste, and if you're happy with the result, then continue doing what you're doing - but I think I'd definitely hesitate to eat a cake that was baked with yogurt instead of butter.

Butter flavored shortening and a touch of water (because butter has water in it too). The key thing here is that you have a have a solid fat because you're beating air bubbles into the butter during the creaming process. These bubbles are needed for the bread to properly rise during baking.

The browning process may be an issue though - shortening has no protein. You're after an umami flavor from the Malliard reaction ... it may be difficult to add that because of the lack of protein. A pinch of MSG maybe, for the umami?