PREHEAT oven to 350° F.
MICROWAVE 1 cup morsels in small, uncovered, microwave-safe bowl on HIGH (100% power) for 1 minute; STIR. The morsels may retain some of their original shape. If necessary, microwave at additional 10- to 15-second intervals, stirring just until smooth; cool.
COMBINE flour, baking powder, baking soda and salt in medium bowl; mix well. Beat butter and sugar in large bowl with electric mixer until creamy. Blend in melted chocolate, egg and vanilla extract. Gradually add flour mixture; mix well. Stir in oats and remaining morsels. Drop by rounded tablespoonfuls onto ungreased baking sheets.
BAKE for 12 to 14 minutes or until set. Cool on baking sheets for 2 minutes; remove to wire rack to cool completely. Store tightly covered.