Pre-heat oven to 350 F. Line two large baking sheets with aluminum foil, shiny side up. Set aside 24 pecan halves, then finely chop the remaining pecans. In a saucepan over low heat, melt butter. Remove pan from heat, stir in brown sugar and remaining ingredients until well blended. Drop mixture by tablespoonfuls 3″ apart onto prepared baking sheets. Press a pecan half into the top of each cookie. Bake 12 minutes. Slide foil with cookies onto a wire rack to cool completely. When cookies are cooled, gently peel away foil.