I found this cake recipe on Cooking Light's website. I made a couple of changes and used Martha Stewart's frosting instead, and I made a couple of changes to that, too.
For the cake--with my changes:
1/2 cup butter (1 Smart Balance stick)
1 cup fat free plain yogurt
1 1/2 cups sugar
2 tsp vanilla
2 cups flour
1 tsp baking soda
1/4 tsp salt
3/4 cup low-fat buttermilk
After reading through the recipe I was unsure that it would work, but the reviews were good and that is the best indicator of how a recipe will turn out. The directions call for whisking the butter and yogurt (they used sour cream) until combined.
Then add the sugar and vanilla and beat on medium speed for 3 minutes. I used the whisk attachment on my mixer to combine the butter and yogurt, then switched to the paddle after adding the sugar.
That looks wrong, doesn't it? I saw that and thought, oh no! After the butter/sugar stage a cake mixture should be the epitome of fluffy, not grainy and so...wrong. At this point I figured my instincts were right and this cake recipe was not going to work. But instead of throwing it all away I thought, why not waste a few more ingredients and add the flour and buttermilk? :)
Add half the flour, baking soda, and salt and beat on low speed until combined. Then add the buttermilk, mix until combined. After adding the last of the flour and mixing (being careful not to overmix), the batter looks like this:
So right! It also may be the best tasting cake batter ever. Seriously delicious. I lowered their suggested temperature to 325 because I used a glass pan and baked for 35 minutes. After it was done I just left it in the pan and placed it on a raised wire rack to cool. Normally I would remove the cake from the pan, but I was just making it for our family and decided to frost it and serve from the pan.
Now the frosting...oh, my. So good. Martha calls for Valrhona cocoa, which is a fancy dutch processed cocoa. (And judging by the amazon.com reviews, overrated.) I didn't have any of that. Or any dutch processed cocoa. In fact, I was almost out of my regular Hershey's cocoa. So, I used:
1/2 cup cocoa
2 1/2 squares baking chocolate
9 1/2 T of butter (I know, weird, but I had to decrease the butter by 2 1/2 T because of the oil in the baking chocolate)
3 1/2 cups powdered sugar
1/2 cup milk
2 tsp vanilla
I melted the baking chocolate in a double boiler
and then poured that chocolate over the butter and cocoa in my mixer bowl and mixed.
I added the rest of the ingredients all at once and beat it until it was creamy. I found that I didn't need to adjust the milk or powdered sugar amounts. Leave it to Martha to get it exactly right.
The frosting was so amazing that I will probably make it the exact same way next time, even if I have a truckload of cocoa. The cake itself was wonderful. I could tell that it wasn't a full fat cake, but it certainly did not diminish the flavor. The best part was that the cake was still every bit as moist the next day. That's a rarity with cake. I will definitely make it again!
The changes I made to the cake recipe were purely for personal taste. I dislike the flavor of sour cream in cakes and plain yogurt can be substituted (with a better result, I think) in equal amounts. I used Martha's frosting because I also dislike cream cheese frostings. Too heavy for me, especially since I prefer no frosting at all. :)