HEAT oven to 350°F. Line 13 x 9-inch pan with foil. Coat with no-stick cooking spray. Combine cake mix, water, oil and eggs in large bowl with electric mixer until moistened. Beat on medium speed for 2 minutes. Fold in walnuts and raisins. Spread evenly in prepared pan.
CUT off corner of pie filling pouch. Make 15 evenly-spaced mounds of filling by squeezing the equivalent of a rounded teaspoon in 3 rows with 5 mounds in each row. Push filling gently down into batter using the back of a spoon.
BAKE 32 to 36 minutes or until toothpick inserted in center comes out clean. Place on wire rack to cool completely.
For Maple Cream Frosting: BEAT frosting and maple extract in medium bowl with electric mixer on medium speed until combined. Invert cooled cake onto serving plate. Remove foil. Frost cake and sprinkle with chopped glazed walnuts.
TIP Glazed walnuts are availabe in your grocer's snack aisle in the nut section.