In a medium bowl, whisk the flour, cocoa, baking powder, salt, cinnamon, and cayenne until well-combined. Alternatively, to use the microwave, add the butter and chocolate to a medium microwave-safe bowl and heat at half power in 30-second intervals, stirring between bursts, until smooth. Set the bowl over a pot of gently simmering water and cook, stirring occasionally, until the chocolate has melted and the mixture is smooth. Place the chocolate and butter in a medium heatproof bowl.
