Mix flour, baking powder and salt; set aside. Beat butter and sugar in large bowl with electric mixer on medium speed until light and fluffy.
Add eggs and vanilla; mix well. Blend in melted chocolate. Gradually add flour mixture, beating well after each addition. Stir in chopped chocolate and pecans.
Drop heaping tablespoonfuls of dough, 2 inches apart, onto ungreased baking sheets.
Bake 11 to 12 minutes or until cookies feel set to the touch. Cool on baking sheets 1 minute.