Preheat the oven to 325 degrees F.
Grease and flour an 11 by 7-inch baking pan or dish with 1 teaspoon of the butter and 1 tablespoon of the flour. Heat the remaining butter and the unsweetened chocolate in a saucepan over low heat, stirring constantly, until melted. In a medium bowl, stir together remaining flour, sugar, cinnamon, and ground chipotle. Add sugar mixture to melted chocolate mixture, stirring to combine. Add eggs, mixing until smooth. Stir in chopped chocolate or chocolate morsels.
Pour mixture into the prepared baking pan or dish. Bake until the center is set, 35 to 40 minutes. Cool completely and then cut into small squares.
Yield: about 24 squares