Preheat oven to 350°. In a large bowl, combine cake mix, eggs, oil and extract; beat on low speed 30 seconds. Beat on medium 2 minutes., Transfer batter to pastry bag; cut a 1/2-in. hole in the tip of bag. Pipe 1-1/2x1-in. hearts onto parchment-lined baking sheets, spacing hearts 1 in. apart., Bake until edges are set, 6-8 minutes. Cool on pans 2 minutes. Remove to wire racks to cool completely., For filling, in a large bowl, beat cream cheese and butter until blended. Gradually beat in confectioners’ sugar until smooth. Stir in chocolate chips. Spread filling on bottoms of half the cookies. Top with remaining cookies. Refrigerate leftovers.