Help! Replacement for buttermilk in chocolate cake
So I have to make a chocolate cake this weekend and I'm a bit stressed 1. because I'm not a big baker and 2. because I also have to turn in my masters dissertation on Monday (not that that's really relevant except that I need to make this cake with a minimum of fuss. ) I found what appears to be a very simple recipe. One layer--plain ingredients, kitchen tools I more or less have. Only snag is that it calls for buttermilk and I live in London (and while it may be available here--big city and all) haven't seen it. How central is it? Is there something I can replace it with? If you live in London is there somewere I can easily get it?
Here's the recipe if any expert bakers can tell from looking how I can work around buttermilk
Aunt Sabella's Black Chocolate Cake with Fudge Icing (from saveur.com)
Makes one 8-inch cake
We adapted the cake recipe from How America Eats and topped it with a frosting also in the book.
FOR THE CAKE:
2 oz. unsweetened chocolate, chopped
5 tbsp. plus 1 tsp. unsalted butter, softened
1 1⁄4 cups sifted flour
1 tsp. salt
1 tsp. baking soda
1 cup buttermilk
1 cup sugar
2 egg yolks
FOR THE FROSTING:
2 1⁄4 cups confectioners' sugar, sifted
5 tbsp. cocoa
6 tbsp. unsalted butter, melted
5 tbsp. hot freshly brewed coffee
1 1⁄2 tsp. vanilla extract
1. Preheat oven to 350º. Melt chocolate in a small heatproof bowl set over a small pot of gently simmering water over medium-low heat, stirring occasionally with a wooden spoon. Remove bowl from heat and set aside until chocolate is cool. Meanwhile, grease an 8" square cake pan with 1 tsp. of the butter and set aside. Sift flour and salt together in a small bowl and set aside. Stir baking soda into buttermilk in another small bowl and set aside.
2. Beat sugar and the remaining 5 tbsp. butter together in a large mixing bowl with an electric mixer on medium speed until light and fluffy, about 2 minutes. Beat in egg yolks, then add melted chocolate and beat until thoroughly combined. Add one-third of the flour mixture, then one-third of the buttermilk mixture, beating well after each addition. Repeat process to use all of both mixtures, then pour batter into prepared pan and bake until a toothpick inserted in center of cake comes out clean, 40–50 minutes. Transfer cake to a rack to cool in pan, then invert onto a cake plate.
3. For the frosting: Sift confectioners' sugar and cocoa together in a medium bowl. Stir in butter, then coffee, then vanilla, mixing well with a wooden spoon after each addition, until frosting is smooth. Ice top and sides of cake with frosting.
A scabt Tablespoon lemon juice in a cup of whole milk will produce a good substitute to use in this recipe.
From what you say it doesn't look like you might, but if you think you will be doing this very often I suggest you search out a powdered B.milk. You can keep it in the pantry forever, and use it as needed.
Plain milk and baking powder (or self rising flour) will also work. Buttermilk provides the acid that reacts with the baking soda to produce CO2. Vinegar is the alternative acid that others are recommending. Baking powder has a powdered acid along with baking soda.