Sourdough Chocolate Cake With Mocha Frosting - cooking recipe

Ingredients

Cake
1 cup sourdough starter (proofed)
1 cup whole milk
2 cups unbleached all-purpose flour (8 1/2 ounces)
1 1/2 cups granulated sugar
1 cup vegetable oil
2 teaspoons vanilla extract
1 teaspoon salt
1 1/2 teaspoons baking soda
3/4 cup natural cocoa powder (not Dutch process)
2 large eggs
Icing
6 cups confectioners' sugar
3/4 cup butter
1/2 cup buttermilk or 1/2 cup plain yogurt
1 1/2 teaspoons espresso powder
1 tablespoon hot water
Drizzle
1/3 cup semi-sweet chocolate chips
1 tablespoon milk
1 tablespoon corn syrup
1/2 cup chopped walnuts (optional) or 1/2 cup pecans (optional)

Preparation

Combine the \"fed\" starter, milk, and flour in a large mixing bowl. Cover and let rest at room temperature for 2 to 3 hours. It won't necessarily bubble, but it may have expanded a bit.
Preheat the oven to 350\u00b0F Lightly grease a 9\" x 13\" pan.
In a separate bowl, beat together the sugar, oil, vanilla, salt, baking soda, and cocoa. The mixture will be grainy.
Add the eggs one at a time, beating well after each addition.
Gently combine the chocolate mixture with the starter-flour-milk mixture, stirring till smooth. This will be a gloppy process at first, but the batter will smooth out as you continue to beat gently.
Pour the batter into the prepared pan.
Bake the cake for 30 to 40 minutes, until it springs back when lightly pressed in the center, and a cake tester inserted into the center comes out clean.
Remove the cake from the oven, and cool on a rack while you make the icing.
Sift the confectioners' sugar into a large mixing bowl, and set it aside.
In a small saucepan set over medium heat, melt the butter and add the buttermilk or yogurt. Dissolve the espresso powder in the hot water, add to the pan, and bring the mixture just to a boil.
Immediately pour the simmering liquid over the confectioners' sugar in the bowl, and beat till smooth.
Pour the warm frosting over the cake.
Combine the chocolate chips, milk, and corn syrup in a microwave-safe cup. Microwave till the chips soften, then stir till smooth.
Drizzle the chocolate over the icing. (This can be done immediately or you can wait until the cake is cooled.).
If desired sprinkle chopped nuts on top.