PREHEAT oven to 325º F.
MICROWAVE chocolate in small, uncovered, microwave-safe bowl on MEDIUM-HIGH (70%) power for 1 minute; STIR. If pieces retain some of their original shape, microwave at additional 10- to 15-second intervals, stirring just until melted. Cool to room temperature.
COMBINE flour, cinnamon and cayenne in medium bowl. Beat brown sugar and butter in large mixer bowl until light and fluffy. Beat in melted chocolate. Stir in flour mixture until blended. Stir in pecans.
SHAPE dough into 1-inch balls; place 2-inches apart on ungreased baking sheets. Flatten with bottom of glass dipped in sugar.
BAKE for 10 to 12 minutes or until edges are set. Cool on baking sheets for 2 minutes; remove to wire racks to cool completely.