To prepare the cake, preheat the oven to 350°F. Spray a 9-by-13-inch baking pan with nonstick cooking spray and lightly dust with flour or cocoa powder.

Sift together the flour, granulated sugar and cocoa powder into a large bowl. Set aside. 

In another bowl, mix together the eggs, butter, salt, baking powder, vanilla, cherries and chocolate chips in the order listed, then add to the flour mixture.

Pour the batter into the prepared pan. Bake until a toothpick inserted into the center of the cake comes out clean, about 25 minutes. Transfer the pan to a wire rack and let cool for 30 minutes before icing.

To prepare the icing, in a saucepan over medium heat, melt the butter and brown sugar, stirring until the sugar is dissolved, then add the milk. Bring to a boil and remove from the heat. 

Sift together the confectioners' sugar and cocoa powder into a small bowl, then blend into the butter mixture and add the vanilla. If the consistency is too stiff, add more milk. 

Quickly spread the icing over the cooled cake, as the icing will set up very fast.