In a large mixing bowl, combine cake mix, protein powder, yogurt, eggs, water and coconut extract. Fold in 1 cup of coconut flakes and mix until well combined.
Spread batter in an even layer in a 9x13-inch baking pan sprayed with nonstick cooking spray.
Bake for 28-30 minutes or until an inserted toothpick comes out clean. Let cake cool completely then top with Cool Whip and remaining 1⁄2 cup coconut flakes.
Refrigerate until serving then cut into 12 slices.