Grind 1 to 1 1/2 tsp. pepper flakes with a mortar and pestle or spice grinder until pieces are small. Combine brownie mix, ground pepper flakes, and cinnamon in a medium bowl; whisk until well blended. Stir in eggs, oil, and water until blended. Add 3/4 cup chocolate morsels to batter; spoon batter into a lightly greased 13" x 9" pan. Bake at 350° for 28 to 31 minutes. Cool completely in pan on a wire rack.
Place 1 cup chocolate morsels and butter in a large glass bowl. Microwave at HIGH 1 minute or until melted; stir in whipping cream. Pour mixture over cooled brownies, spreading to form a thin even layer. Place remaining 1/4 cup chocolate morsels in a 1-cup glass measuring cup, and microwave at HIGH 30 seconds or until melted. Pour melted chocolate in a zip-top plastic freezer bag; snip a tiny hole in 1 corner of bag. Pipe a zigzag drizzle over iced brownies; sprinkle lightly with chile caribe flakes, if desired. Refrigerate brownies for easy cutting.
Caribe red pepper flakes are typically medium heat, but not overwhelming. Find them on the spice aisle or order a jar from www.penzeys.com or www.thespicehouse.com.