PREHEAT oven to 375° F.
COMBINE flour, oats, baking soda and salt in medium bowl. Beat brown sugar, butter, granulated sugar and vanilla extract in large mixer bowl until creamy. Add eggs, one at a time, beating well after each addition. Gradually beat in flour mixture. Stir in 3/4 cup SWIRLED™ Morsels. Cover; refrigerate for 30 minutes or until firm.
ROLL dough into 1-inch balls and place on ungreased baking sheets. If dough balls become warm, refrigerate until firm.
BAKE for 8 to 10 minutes or until sides are set. Press 1/2-inch deep and quarter-size wide pockets into centers of cookies with back of small spoon. Fill pockets with remaining SWIRLED™ Morsels while cookies are still warm. Remove to wire racks to cool completely.
PLACE milk chocolate morsels in small, heavy-duty plastic bag. Microwave on MEDIUM-HIGH (70%) power for 30 seconds; knead to mix. Microwave at additional 10-second intervals, kneading until smooth. Cut a small hole in corner of bag; squeeze to drizzle over cookies.