In a medium saucepan, melt the butter, Shortening and then add the cocoa. Whisk together to combine. Meanwhile, bring 1 cup water to a boil. When the butter is melted, pour the boiling water into the pan. Allow it to bubble for a moment, then turn off the heat. Pour the chocolate mixture into the flour mixture. Stir together for a moment to cool the chocolate, then pour in the egg mixture. Stir together until smooth, then pour into an ungreased 15 1/2 x 10 1/2 jelly roll pan (or rimmed baking sheet) and bake at 400 degrees for 20 minutes.