PREHEAT oven to 350°F. Mix flour, brown sugar, 1/2 cup of the granulated sugar and the cinnamon; cut in butter using pastry blender or two knives until mixture resembles coarse crumbs. Stir in walnuts. Reserve 2 cups of the crumb mixture for topping; press remaining crumb mixture firmly onto bottom of 13x9-inch baking pan.
BEAT cream cheese and milk with electric mixer on medium speed until well blended. Add remaining 1/4 cup granulated sugar, the egg and vanilla; mix well. Pour over crust. Top with apples; sprinkle with reserved crumb mixture.
BAKE 30 min. Cool completely. Cut into 32 bars to serve. Store in tightly covered container in refrigerator.