Place oven rack to the lowest position. Preheat oven to 350 degrees. Lightly coat two 8-inch cake pans with nonstick cooking spray, set aside.
Blend cake mix and raspberry lemonade in large bowl at low speed until moistened (about 30 seconds). Beat at medium speed for 1 minute. DO NOT OVERBEAT.
Mash ¼ cup of fresh raspberries (about 8). Fold in mashed raspberries, zest from one lemon and 2 Tbsp of lemon juice from the same lemon. Divide batter equally between both cake pans – about 2 cups in each.
Bake for 35 to 40 minutes or until cake top is golden brown and cracked, looks very dry and is warm to the touch. Do not underbake. Hang pans upside down on heat-proof glass dish until they slip out, place upright on cooling racks. Allow cakes to cool completely before frosting, about 1-2 hours.
Transfer Cool Whip® to a large bowl and fold in food coloring until desired pink-ness. Spread a generous amount on top of one cake. Place other cake on top of frosted cake and spread remaining Cool Whip® evenly over both cakes.
Cut the remaining lemon in half, then make ¼-inch slices. Line the bottom of the cake with the lemon slices and top with fresh raspberries. Keep refrigerated until ready to serve!