Preheat oven to 325 degrees F. Line a 13x9x2-inch baking pan with foil, extending the foil over the edges of the pan. Lightly coat foil with nonstick cooking spray; set aside. In a small saucepan, combine chocolate and butter. Cook and stir over low heat until melted and smooth. Cool slightly. In a small bowl, combine flour and cocoa powder; set aside.
In a large bowl, combine sugar, espresso coffee powder, cinnamon, and chipotle powder. Add chocolate mixture. Beat with an electric mixer on medium speed for 1 minute, scraping side of bowl occasionally. Add eggs, one at a time, beating on low speed after each addition just until combined. Beat in vanilla just until combined. Add flour mixture, 1/2 cup at a time, beating on low speed just until combined. Beat on medium speed for 1 minute more. Spread batter evenly into prepared pan.
Bake in preheated oven for 35 to 40 minutes or until edges start to pull away from the sides of the pan. Cool in pan on a wire rack. Using the edges of the foil, lift the uncut brownies out of the pan. Sprinkle with unsweetened cocoa powder. Cut into bars. Makes 32 bars.
Layer bars between waxed paper in an airtight container; cover. Store at room temperature for up to 3 days or freeze for up to 3 months.