Preheat oven to 350 degrees F. Line 8-inch square baking pan with foil, with ends of foil extending over sides of pan. Combine wafer crumbs, 1/2 cup flour and the brown sugar in bowl. Cut in margarine with pastry blender or two knives until mixture resembles coarse crumbs; press firmly onto bottom of prepared pan. Bake 15 min.
Meanwhile, beat Neufchatel cheese and granulated sugar with electric mixer on medium speed until well blended. Add eggs and 2 Tbsp. flour; mix well. Blend in 1 Tbsp. lemon peel, the lemon juice and baking powder; pour over crust.
Bake 25 to 28 min. or until center is set. Cool completely. Cover and refrigerate at least 2 hours or overnight. Sprinkle with powdered sugar and remaining 2 Tbsp. lemon peel just before serving.
