Preheat your oven to 350°F (175°C) and prepare three 9-inch cake pans by greasing and flouring them, or using non-stick baking spray.
In a blender, combine buttermilk, fresh strawberries, and freeze-dried strawberries. Blend until smooth and set aside.
Separate the eggs, discarding the yolks, and let the whites sit at room temperature for about 30 minutes.
In a medium bowl, mix flour, baking powder, baking soda, and salt. Set aside.
In a stand mixer, whip butter for 30 seconds, then add sugar and beat until combined. Stir in vanilla.
Add the room-temperature egg whites and beat for 3 minutes until the batter is pale and light.
Alternate adding the blended strawberry mixture and the flour mixture to the batter, beating just until combined after each addition.
Divide the batter evenly among the three prepared cake pans, tap them gently to even out the batter, and bake at 350°F (175°C) for 30 minutes or until a toothpick inserted into the center comes out clean.
Let the coconut strawberry cakes cool in the pans for 10 minutes, then transfer them to a cooling rack to cool completely.