Heat oven to 375°F. In large bowl, beat brown sugar, granulated sugar, butter and shortening with electric mixer on medium speed until light and fluffy. Beat in vanilla and egg until well blended. On low speed, beat in flour, baking soda and salt until well blended. Stir in semisweet chocolate, white chocolate and pecans.
Onto ungreased cookie sheets, drop dough by tablespoonfuls 2 inches apart.
Bake 9 to 12 minutes or until light golden brown. Cool 1 minute; remove from cookie sheets to cooling racks.