FOOD WISE: Learning a lot from a chocolate layer cake



Chef Renee's grandson, Nate, makes chocolate cupcakes. (Photo by Renee Morgan)

The last couple of weeks, we’ve talked all things chocolate. At the risk of making you think I’m chocolate obsessed, there is a bit more to discuss. After this, you’ll be a chocolate expert. You’ll impress both friend and foe with your chocolaty prowess!

The last couple of weeks, you’ll remember I’ve written about the kinds of chocolate, percentages of cocoa butter in chocolate, tempering chocolate, dutch-processed versus regular chocolate, antioxidant benefits of chocolate and I’ve shared some yummy chocolate recipes.

At the risk of getting all sciency on you again, I want to share some research I did on chocolate cake when I worked at America’s Test Kitchen. Research on chocolate cake, you ask? What kind of job is that? Only the most awesome job on the planet!

The reason I think you should know about this in regards to your total chocolate education is that there is a lot to be learned about chocolate in general from the proper construction of a basic chocolate layer cake that can be transferred to other applications.

Cookbooks are filled with a variety of chocolate layer cake recipes, which tend to lean closely to the yellow cake formula, including the addition of some kind of dairy. The difference is the addition of chocolate to the mix. The recipes can be truly maddening. One promises an especially fudgy and rich cake, the next guarantees and light and tender one. The secret to the recipe is supposed to be the Dutch-processed cocoa, or dark brown sugar, or sour cream, or buttermilk, or some special mixing method, or holding your mouth the right way on a Tuesday in summer in the middle of a snowstorm between 2-2:15 p.m. during an elephant stampede. You can fill in the blank with just about anything.

Part of the research we did at America’s Test Kitchen involved baking and comparing dozens of different chocolate cakes. In the process, we discovered a couple of general principles that apply to whatever type of chocolate layer cake you are making. Perhaps more important, we also learned a great deal about how various ingredients function and what results they produce, so that each of these recipes delivers exactly the type of chocolate cake it promises.

Bakers have argued endlessly over whether cocoa-based chocolate cakes are best made with standard American cocoa, like Hershey’s, or with a European-style cocoa, such as Droste, that has been alkalized, or “dutched” to neutralize some of the natural acid.

In testing, we prepared several recipes using both types of cocoa and found that there was not an enormous difference. Cakes made with the American cocoa were a little blacker and had a slight bitter edge. In the “dutch” processed cocoa cakes, the chocolate flavor was a bit more mellow but also fainter. When we conducted blind taste tests, these distinctions turned out to be minor, and the tasters like both versions just fine. However, since the two different cocoas react very different with leaveners, we ended up basing the recipes on natural cocoa, as it is more widely available.

In another round of experiments, we tested making the cake with cocoa and water versus just the powdered cocoa. In cakes made with cocoa and water, the chocolate flavor was much stronger and the color twice as dark when the cocoa was first dissolved in boiling water rather than simply being mixed into the batter dry. From this discovery on, the folks at America’s Test Kitchen have recommended this procedure for any cocoa-based chocolate cake in which water is the liquid. Cocoa should always be used as the chocolate source in butter based chocolate cakes.

The next thing to test was how dairy – sweet milk, buttermilk, yogurt, sour cream – effects the cake. Sour cream and buttermilk have a seductively mouthwatering effect in chocolate cake recipes, but many bakers have reservations about using milk products when baking with chocolate. We found that hot chocolate prepared with water (with a spoonful of cream added for richness, if you wish) has a far more intense flavor that hot chocolate made with milk. If this is so, milk being a flavor-blocker in hot chocolate, why wouldn’t a dairy product have a similar effect in chocolate cakes? The experiment proved that they do, but it was more complicated than expected.

When we used milk in place of the water, the chocolate flavor was a little more muted. The cake was a little less tender and more crumbly. It did have a pleasantly substantial feel in the mouth, like the old fashioned one of childhood. Buttermilk and yogurt proved to be problematic. They both added a velvety texture and nice moisture, but they also compacted the cake and made them seem chewy, a little hard and a bit pasty. If the sweet milk had a gentling effect on the chocolate, the buttermilk and yogurt killed it completely. The moral of that story is not that buttermilk or yogurt can’t used but that it should be used in very limited quantities. Copious amounts of sugar and fat seems to mitigate the chocolate-blocking effect of the buttermilk. Buttermilk seemed to make the cake more tart and, strangely enough, sour cream seemed to make the cake sweeter. To use sour cream in a chocolate layer cake, it was necessary to decrease the butter to compensate for the milk fat in the sour cream.

Overall, the best plan was to stick with standard American cocoa and milk for an old-fashioned chocolate cake that would be sturdy enough for a rich chocolate frosting with a pleasantly crumbly texture. Here’s the recipe we developed for Old-Fashioned Chocolate Layer Cake and Chocolate Cream Frosting. It also make a great cupcake.

Old-Fashioned Chocolate Layer Cake

serves 12 in a cake

1 1/4 cups unbleached all purpose flour, plus more for dusting

12 tablespoons unsalted butter, softened but still cool

1 1/4 cups sugar

2 large eggs, at room temperature

1/2 teaspoon baking soda

1/2 teaspoon salt

1/2 cup non-alkalized cocoa, such as Hersey’s, sifted

2 teaspoon instant espresso or coffee powder

1 cup plus 2 tablespoons whole milk

2 teaspoons vanilla extract

1 recipe Rich Chocolate Cream Frosting – following

1. For the cake: Adjust an oven rack to the middle position and heat the oven to 350℉. Generously grease two 8-inch round cake pans and cover the pan bottoms with rounds of parchment paper or waxed paper. Grease the parchment rounds and dust with flour, tapping out the excess.

2. Beat the butter in the bowl of a stand mixer at medium-high speed until smooth and shiny, about 30 seconds. Gradually sprinkle in the sugar; beat until the mixture is fluffy and almost white, 3 to 5 minutes. Add the eggs 1 at a time, beating 1 full minute after each addition.

3. Whisk the flour, baking soda, salt, cocoa, and instant espresso in a medium bowl. Combine the milk and vanilla in a liquid measuring cup. With the mixer at the lowest speed, add about a third of the dry ingredients to the batter, followed immediately by about a third of the milk mixture; mix until the ingredients are almost incorporated into the batter. Repeat the process twice more. When the batter appears blended, stop the mixer and scrape the sides of the bowl with a rubber spatula. Return the mixer to low speed; beat until batter looks satiny, about 15 seconds longer.

4. Divide batter evenly between the prepared pans. With a rubber spatula, spread the batter evenly. Bake the cakes until they feel firm in the center when lightly pressed and a toothpick inserted into the center comes out clean, 23-30 minutes. Transfer the pans to wire racks and cool for 10 minutes. Run a knife around the perimeter of each pan, invert the cakes onto racks and peel off the paper liners. Reinvert the cakes and cool completely.

Rich Chocolate Cream Frosting

Makes about 3 cups

16 ounces bittersweet or semisweet chocolate, chopped fine

1 1/2 cups heavy cream

1/3 cup light corn syrup

1 teaspoon vanilla extract

Place the chocolate in a heatproof bowl. Bring the heavy cream to a simmer in a small saucepan over medium-high heat; pour over the chocolate. Add the corn syrup and let stand 3 minutes. Whisk gently until smooth; stir in the vanilla. Refrigerate 1 to 1 1/2 hours, stirring every 15 minutes, until the mixture has a spreadable consistency. This frosting does not keep well, so it should be used within a day.