Chocolate Sheet Cake

INGREDIENTS

• 6 tablespoons milk
• 1/2 cup buttermilk
• 1 pound powdered sugar
• 4 heaping tablespoons cocoa powder
• 1/4 teaspoon salt
• 2 cups sugar
• 1 teaspoon vanilla extract
• 2 sticks butter
• 1 3/4 sticks butter
• 2 cups all-purpose flour
• 1/2 cup finely chopped pecans, optional
• 1 teaspoon baking soda
• 2 large eggs