Coat three 8 inch round cake pans with cooking spray and line with parchment circle on the bottom.
Whisk the flour, cocoa powder, baking powder, and salt in a medium bowl. Set aside.
Pulse the coconut in a food processor until it is very finely chopped.
In a large bowl, beat the butter, sugar, and coconut with an electric mixer on medium speed until thoroughly combined, about 2 minutes.
Add the eggs, one at a time, beating well after each addition. Beat in the vanilla.
In a small bowl, stir together the red food coloring, buttermilk, and coconut milk.
Add the dry ingredients to the butter mixture in 3 batches, alternating with the buttermilk mixture, beginning and ending with the dry ingredients. Stop and scrape down the bowl twice.
In a small bowl, stir together the vinegar and the baking soda. With the mixer set at medium speed, beat the vinegar mixture into the batter.
Divide the batter evenly into the cake pans.
Bake until a toothpick inserted in the center of the cake comes out clean, 25 to 30 minutes. Cool on a rack.
Beat the cream cheese with the butter until light and fluffy. Mix in the vanilla and coconut cream. Slowly add the confectioners' sugar 1/2 a cup at a time until the mixture reaches the consistency of frosting and can hold it's shape. Store in an airtight container at room temperature until ready to use.
In a small bowl, whisk together the milk and vanilla to make the cake soak.
Dip a pastry brush in the cake soak and brush the soak over the cake rounds.
Use an offset spatula to spread one-fifth of the frosting in an even layer over the cake.
Sprinkle one-third of the shredded coconut evenly over the frosting. Use the back of your hand to press them in place.
Set the second cake round on top of the frosting, and repeat the process for layer 1 (if 1 of your 3 cake rounds is uglier than the other, use it here on the bottom and save the prettier one for the top). Repeat with remaining cake layer.
Cover the top of the cake with the remaining frosting and frost the sides of the cake. Garnish the frosting with the remaining coconut.
Transfer the cake to the freezer and freeze for a minimum of 12 hours to set the cake and filling. The cake will keep in the freezer for up to 2 weeks.
At least 3 hours before you are ready to serve the cake, pull the cake out of the freezerand transfer the cake to a platter or cake stand. Allow it defrost in the fridge for a minimum of 3 hours (wrapped well in plastic, the cake can be refrigerated for up to 5 days).