Split 11 cookies, leaving filling on 1 side of each cookie. Reserve split cookies with filling for brim of hat. Coarsely chop plain split cookies and remaining 4 whole cookies; set aside.

Mix cake mix, water, oil and eggs in large bowl with electric mixer at low speed until moistened. Beat 2 minutes at medium speed. Stir in chopped cookies. Pour 3 cups batter into greased and floured 9-inch round cake pan and 3/4 cup batter into greased and floured 10-ounce custard cup.

Bake at 350°F for 25 to 35 minutes or until toothpick inserted near centers comes out clean. Cool in pan and custard cup on wire racks 10 minutes; remove from pan and custard cup. Cool completely. (Divide remaining batter among 6 to 8 paper-lined 2-1/2-inch muffin pan cups. Bake at 350°F for 15 to 25 minutes. Cool in muffin pan on wire rack 5 minutes. Remove from pan, cool completely, and save cupcakes for another use.)

Place 9-inch cake layer on serving plate; frost top of cake with some of the frosting. Place cake round from custard cup, top side down, slightly off-center on top of cake layer reserve a cup frosting for cupcakes; frost side and top of bonnet with remaining frosting. Sprinkle with coconut, pressing gently into frosting.

Half the reserved split cookies, place, filling side up and rounded edge out, around brim of hat. Place a ribbon around the center cake round to resemble a bonnet bow. Decorate with cake-top flowers. Decorate cupcakes with reserved frosting and candies.