This beautifully prepared Zebra Cake is as delicious as it is pretty to look at. It has a dense texture and firm crumb, and a hint of tanginess from the sour cream. Everyone's favorite part is the rich and glossy chocolate glaze! It provides an elegant flourish to a classic cake.
7tablespoons(100 grams) unsalted butter, cut into chunks
Walnut halvesfor garnish
Place the oven rack in the lower third of the oven and preheat to 325°F.
In the bowl of an electric mixer fitted with the paddle attachment, cream together the butter and sugar at medium-high speed. When the mixture is smooth and somewhat sandy, add the eggs one at a time, making sure to fully incorporate each egg before adding another. Scrape down the sides of the bowl, then gradually add the sour cream and beat to combine.
Pour the vinegar into a very small bowl. Add the baking soda, and once it fizzes quickly add it to the batter. Mix. Add the vanilla extract and mix again.
Add the flour and mix until just combined. Do not over-mix. Reserve 3 cups batter to another bowl (half the batter). To the mixer bowl, add the cocoa powder and mix to combine. You will now have a bowl of vanilla cake batter and a bowl of chocolate cake batter.
Grease a 9-inch springform pan. Pour ¼ cup of vanilla batter into the center of the pan. Pour ¼ cup of chocolate batter directly into the center of the vanilla batter. Repeat, using all of both batters, alternating colors. The layers will spread out on their own, but a gentle rap of the pan onto the table or counter will help the batter even out, if needed.
Bake for 70 to 75 minutes, or until a toothpick inserted into the center comes out clean (the top may crack a bit, but is easy to cover up with the chocolate glaze later). Let cool for 15 minutes, then remove the sides of the springform pan and cool completely.
Select a serving dish or platter and place 3 pieces of aluminum foil around the perimeter, leaving the center clear. Remove the cake from the springform pan base and place in the center of the pieces of foil. This will make for easy cleanup after you glaze the cake.
To make the glaze, combine the confectioners’ sugar and cocoa powder in a saucepan. Add the milk and place the pan over medium heat. Stir constantly until the mixture is completely dissolved and smooth. Add the butter and continue mixing until smooth. Add the vanilla extract and remove from the heat. Allow the glaze to cool for about 30 minutes to allow it to slightly thicken. Stir periodically.
Spoon the sauce over the center of the top of the cake, and use a rubber spatula to gently smooth it over the surface and sides of the cake. Use the rubber spatula as needed to push some of the extra chocolate glaze on the foil back up the sides of the cake as needed to smooth it out.
Line the perimeter of the top of the cake with walnut halves. Allow the glaze to set a bit, and then gently pull the foil pieces away and discard them before serving. This cake will keep at room temperature for several days. Store leftovers in an air-tight container.
You may substitute plain yogurt for the sour cream.
We use red wine vinegar, but you can also try white wine vinegar or even distilled white vinegar. The important part is the acidity it imparts, and less the particular flavor of the vinegar.
I cannot stress enough, please make sure you let your chocolate glaze rest and cool a bit before pouring over your cooled cake.
If you don't have walnut halves, you may sprinkle walnut pieces around the circumference of the cake instead. It will have a more rustic look, but still be absolutely delicious.
Even though this is a 9-inch cake, it comfortably serves 12 people because it's a relatively dense cake, and you can serve more moderate slices to each guest.