Heat oven to 350 degree F. Grease a 13x9-inch baking pan. Line bottom with waxed paper; grease and flour paper.

Whisk together flour, sugar, baking soda, baking powder and salt in a large bowl. Whisk cocoa and boiling water in a medium bowl until smooth. Stir cocoa into dry ingredients with a rubber spatula. (Mixture will be dry.) Whisk eggs, buttermilk, vanilla and butter together in a medium bowl. Whisk buttermilk mixture into cocoa mixture, until smooth. Pour batter into prepared pan. Bake 40 minutes, until a toothpick inserted in center of cake comes out clean.

Make frosting: Meanwhile, place Ibarra chocolate (or semisweet chocolate and cinnamon) and butter in a medium microwaveproof bowl. Cover bowl with plastic wrap, turning back one section to vent. Microwave on High 1-1/2 minutes, until chocolate is melted; stir until smooth. Add cream. Cover and microwave 1-1/2 minutes more, just until cream is hot. Stir until frosting is completely smooth and shiny.

Cool cake in pan on wire rack 5 minutes. Pour frosting evenly over hot cake. Sprinkle pecans over top. Cool cake completely. Makes 12 servings.

Available in most Hispanic supermarkets.