This showstopper features a shiny chocolate glaze, crunchy almonds, and coconut both inside and out. We developed this recipe with Fluff brand marshmallow crème. When working with the marshmallow crème, grease your spatula and the inside of your measuring cup with vegetable oil spray to prevent sticking. Cream of coconut is often found in the soda and drink-mix aisle of the grocery store. One 15-ounce can is more than enough for the cake; make sure to stir it well before using because it separates as it stands.
1. FOR THE COCONUT CAKE ROUNDS: Adjust oven rack to middle position and heat oven to 325 degrees. Grease three 8-inch round cake pans and line with parchment paper.
2. Whisk egg and whites, cream of coconut, water, vanilla, and coconut extract together in 2-cup liquid measuring cup. Using stand mixer fitted with paddle, mix flour, sugar, baking powder, and salt on low speed until combined, about 5 seconds. Add butter, 1 piece at a time, and mix until only pea-size pieces remain, about 1 minute.
3. Add half of egg mixture, increase speed to medium-high, and beat until light and fluffy, about 1 minute. Reduce speed to medium-low, add remaining egg mixture, and beat until incorporated, about 30 seconds. Using rubber spatula, give batter final stir by hand.
4. Divide batter evenly among prepared pans and smooth tops with rubber spatula. Bake until tops are light golden and toothpick inserted in centers comes out clean, 22 to 24 minutes, rotating pans halfway through baking. Let cakes cool in pans on wire rack for 10 minutes. Remove cakes from pans, discarding parchment, and let cool completely on rack, about 2 hours.
5. FOR THE COCONUT FILLING: Using stand mixer fitted with whisk attachment, whip butter and salt on medium speed until smooth, about 1 minute. Reduce speed to low and slowly add sugar. Increase speed to medium and whip until smooth, about 2 minutes, scraping down bowl as needed. Add marshmallow crème and coconut extract, increase speed to medium-high, and whip until light and fluffy, 3 to 5 minutes. Using rubber spatula, fold in coconut until thoroughly combined.
6. FOR THE CHOCOLATE GLAZE AND DECORATION: Combine coconut and almonds in small bowl; set aside. Combine cream and corn syrup in medium saucepan and bring to simmer over medium heat. Off heat, stir in chocolate and vanilla until smooth. Let sit until slightly thickened, about 10 minutes.
7. Place 1 cake layer on rimmed baking sheet. Spread half of filling evenly over cake. Top with second cake layer, then spread remaining filling evenly over top. Top with third cake layer. Smooth any filling that has been pushed out from between layers around sides of cake.
8. Pour glaze evenly over top and sides of cake. Let sit until glaze is nearly set, about 20 minutes. Gently press reserved coconut-almond mixture onto sides of cake. Refrigerate cake until glaze is fully set, about 30 minutes. Using 2 large spatulas, transfer cake to plate or pedestal. Serve.