PREHEAT oven to 350°F. Chop 20 of the cookies; finely crush remaining 12 cookies. Set aside.
PREPARE cake batter as directed on package. Add sour cream; mix well. Gently stir in chopped cookies. Pour into greased and floured 13x9-inch baking pan. Mix crushed cookies, pecans, coconut, brown sugar and cinnamon in small bowl; stir in margarine. Sprinkle over batter.
BAKE 40 minutes or until toothpick inserted in center comes out clean. Cool completely. Drizzle with Simple Powdered Sugar Icing; let stand until set. Cut into 24 squares to serve.