HEAT oven to 350ºF.
LINE 13x9-inch pan with foil, with ends of foil extending over sides. Microwave butter in large microwaveable bowl on HIGH 1 to 1-1/2 min. or until melted. Add cake mix and 1 egg; beat with mixer until well blended. Press 2/3 of the mixture onto bottom of prepared pan.
BEAT cream cheese and sugar with mixer until well blended. Add remaining egg, zest and juice; mix well. Pour over crust; top with berries. Pinch small pieces of the remaining cake mix mixture between your fingers; press lightly into cream cheese layer.
BAKE 55 min. to 1 hour or until toothpick inserted in center comes out clean. Cool completely. Use foil handles to lift dessert from pan before cutting into bars. Keep refrigerated.
This recipe was found at: http://www.kraftrecipes.com/recipes/lemon-blueberry-crumb-bars-124533.aspx