TO MAKE THE PINEAPPLE FILLING:

1. Combine the sugar and cornstarch in a large saucepan.
2. Stir in the pineapple, including the juice, and the water.
3. Cook over medium-high heat, stirring regularly until mixture thickens and come to a boil, about 10 minutes.
4. Allow to boil for 1 1/2 minutes, then remove from heat.
5. Stir in vanilla extract and set aside to cool.

TO MAKE THE CAKE LAYERS:

6. Prepare three 8 inch cake pans with parchment paper circles in the bottom and grease the sides. Preheat oven to 350°F (176°C).
7. In a large mixing bowl, cream the butter and sugar together until light in color and fluffy, about 3-4 minutes. Do not skimp on the creaming time.
8. Add sour cream and coconut extract and mix until well combined.
9. Add egg whites in two batches, mixing until well combined after each. Scrape down the sides of the bowl as needed to be sure all ingredients are well incorporated.
10. Combine dry ingredients in a separate bowl, then combine the milk and water in a small measuring cup.
11. Add half of the dry ingredients to the batter and mix until well combined. Add the milk mixture and mix until well combined. Add remaining dry ingredients and mix until well combined. Scrape down the sides of the bowl as needed to be sure all ingredients are well incorporated.
12. Divide the batter evenly between the cakes pans and bake for about 21-23 minutes, or until a toothpick comes out with a few crumbs.
13. Remove the cakes from the oven and allow to cool for about 2-3 minutes, then remove to cooling racks to cool completely.

TO MAKE THE BUTTERCREAM:

14. In a large mixer bowl, beat the butter and shortening together until smooth.
15. Slowly add half of the powdered sugar and mix until smooth.
16. Add the coconut extract and 5-6 tablespoons of water or milk and mix until smooth.
17. Slowly add the remaining powdered sugar and mix until smooth. Add additional water or milk, as needed.

TO ASSEMBLE THE CAKE:

18. To toast the coconut, preheat the oven to 400°F (204°C). Spread the coconut out evenly over a parchment lined cookie sheet. Bake until toasted, about 5-8 minutes, tossing regularly so that it toasts evenly.
19. To put the cake together, use a large serrated knife to remove the domes from the top of the cakes so that they’re flat. Place the first cake on a serving plate or a cardboard cake round.
20. Pipe a dam of coconut frosting around the edge of the cake, then spread about 1 cup of pineapple filling evenly into the center.
21. Add the second layer of cake and another dam of coconut frosting and cup of pineapple filling. You may end up with a little bit of pineapple filling left over.
22. Top the cake with the remaining layer and frost the outside of the cake. Refer to my tutorial on how to frost a smooth cake with buttercream, if needed, or watch the video above.
23. Press the toasted coconut into the sides of the cake.
24. Use the remaining buttercream to pipe swirls around the top of the cake. I used Ateco tip 808.
25. Top the swirls with cherries and add some sliced pineapple, if desired.