Spray 2 (9-inch) round pans with cooking spray; cover bottoms with parchment. Prepare cake batter as directed on package. Add dry drink mix to batter; mix well. Pour into prepared pans.
Bake 28 to 30 min. or until toothpick inserted in centers comes out clean. Cool cakes in pans 10 min.; remove from pans to wire racks. Cool completely.
Mix sour cream and sugar in large bowl until blended; gently stir in COOL WHIP. Place 1 cake layer on plate; spread 1/2 cup COOL WHIP mixture onto cake. Sprinkle with half the berries. Cover with remaining cake layer. Frost top and side of cakes with remaining COOL WHIP mixture; top with remaining berries. Refrigerate 2 hours.
Stir 1 tsp. lemon zest into COOL WHIP mixture before filling and frosting cake.
Substitute raspberries for the blueberries.
Prepare cakes as directed; cool completely. Tightly wrap each layer in plastic wrap and freeze up to 2 weeks. When ready to serve, thaw cakes at room temperature before preparing COOL WHIP mixture and using to fill and frost cakes.
Calories From Fat
% Daily Value*
Total Fat 12g
Saturated Fat 5g
Trans Fat 0g
Total Carbohydrates 44g
Dietary Fibers 1g
* Percent Daily Values are based on a 2,000 calorie diet.
* Nutrition information is estimated based on the ingredients and cooking instructions as described in each recipe and is intended to be used for informational purposes only. Please note that nutrition details may vary based on methods of preparation, origin and freshness of ingredients used.