CHOCOLATE-BUTTERMILK SHEET CAKE

Chocolate-Buttermilk Sheet Cake image

Provided by Mary Charlotte McCall

Yield Makes 24 servings

Number Of Ingredients 15

1 cup water
1 cup (2 sticks) unsalted margarine, room temperature
1/2 cup plus 3 tablespoons unsweetened cocoa powder
1/2 cup vegetable oil
2 teaspoons vanilla extract
1 teaspoon baking soda
2 cups sugar
2 cups all-purpose flour
1/2 teaspoon salt
1/2 cup buttermilk
2 large eggs
1 cup semisweet chocolate chips
1 pound powdered sugar (about 4 cups)
1/3 cup whole milk
1 cup chopped pecans or walnuts

Steps:

Preheat oven to 350°F. Butter and flour 15 1/2 x 10 1/2 x 1-inch baking sheet. Whisk 1 cup water, 1/2 cup margarine, 1/2 cup cocoa powder, vegetable oil, 1 teaspoon vanilla and baking soda in large bowl to blend. Whisk in sugar, flour, salt, then buttermilk and eggs. Spread batter in prepared baking sheet. Sprinkle batter with semisweet chocolate chips. Bake cake until tester inserted into center comes out clean, about 20 minutes. Transfer cake in pan to rack.
Meanwhile, melt remaining 1/2 cup margarine in heavy medium saucepan over medium heat. Remove from heat. Whisk in powdered sugar, whole milk, remaining 3 tablespoons cocoa powder and 1 teaspoon vanilla.
Spread frosting over warm cake. Sprinkle with nuts. Cool cake completely in pan. (Can be prepared 1 day ahead. Cover and let stand at room temperature.) Cut into 24 pieces.