chocolate cake squares with eggnog sauce

Ingredients

• CAKE:
• 1 1/2 teaspoons baking soda
• 1 cup buttermilk or sour milk (3/4 c. milk and 1/4 c lemon juice)
• 3/4 cup hershey's cocoa powder
• 3/4 cup boiling water
• 1/4 cup butter, softened
• 1/4 cup solid shortening-buttery crisco ,i use
• 2 cups granulated sugar
• 2 large eggs
• 1 tablespoon vanilla-yes tablespoon
• 1/8 teaspoon salt- that's a pinch
• 1 3/4 cups all purpose flour
• EGGNOG SAUCE:
• 1 tablespoon cornstarch
• 2 tablespoons cold water
• 1 1/3 cups milk
• 1/4 cup granulated sugar
• 3 large egg yolks, beaten
• 2 teaspoons brandy vanilla extract or bourbon vanilla extract
• 2 or 3 dashes ground nutmeg