Preheat oven to 375 degrees. Melt chocolate and butter in double boiler, add sugar, brown sugar, eggs and vanilla. Place chocolate mixture in a mixing bowl and fold in flour, salt and baking powder. Add pecans and chile powder. Pour mixture into a deep 9 by 13 greased pan and bake in oven for 1 hour or until toothpick inserted in center comes out clean. Cut into 3-inch squares. Serve with Cajeta Sauce, cinnamon ice cream, and sifted cocoa powder.
Stir together the milk, sugar, corn syrup, and cinnamon stick in medium size heavy pot or Dutch oven. Bring to a boil. Dissolve the baking soda in 1 tablespoon water, remove the milk from the heat, and stir in the soda mixture, having a spoon ready to stir the mixture down if it bubbles up. Cook, stirring frequently, over medium heat, until the mixture thickens into a pale-gold syrup, about 25 minutes. At this point, begin stirring very frequently as the mixture thickens into a caramel-brown syrup that's the consistency of maple syrup, about 10 minutes more. Strain the cajeta sauce through a fine mesh strainer set over a large measuring cup. Let cool for a few minutes, then stir in the sherry, rum or brandy (plus a little water, if necessary, to bring it to 1 1/2 cups). Refrigerate covered. When cold, the cajeta sauce should have the consistency of thin corn syrup.