Preheat oven to 350°. Grease and lightly flour a 13 x 9-inch baking pan; set aside.
Beat cake mix, Hellmann's® or Best Foods® Real Mayonnaise, water and eggs in large bowl with electric mixer on low speed 30 seconds. Beat on medium speed, scraping sides occasionally, 2 minutes. Pour into prepared pan.
Combine coconut, brown sugar and pecans in small bowl. Set aside.
Bake 20 minutes; sprinkle with coconut mixture. Continue baking 15 minutes or until toothpick inserted in center comes out clean. Cool completely on wire rack. To serve, cut into squares.