HEAT oven to 350ºF. Beat cream cheese, butter, sugar and vanilla with electric mixer until blended. Add flour and baking soda; mix well. Divide dough in half. Mix half of the dough with chocolate. Divide each in half again. You will have two white and two chocolate pieces.

ROLL or press one of the white dough pieces into 10x8-inch rectangle on lightly floured surface; top with one of the chocolate pieces, broken into smaller pieces. Press gently into white dough. Start at one of the log sides to tightly roll up dough to form log; wrap with plastic wrap. Repeat with remaining dough. Refrigerate 1 hour.

CUT into slices, each about 1/4 inch thick; place, 2 inches apart, on baking sheets. Bake 10 to 12 min. or until lightly browned. Let stand on baking sheets 2 min.; remove to wire racks. Cool completely.