1 (18 ounce) box white cake mix
1 cup coconut milk, divided
2/3 cup water
2 egg whites
1 tablespoon unflavored gelatin
2 cups heavy cream
6 tablespoons sugar
1 teaspoon lemon extract
shredded coconut (amount needed to sprinkle over entire cake)
1 cup sugar
1/2 teaspoon salt
6 tablespoons cornstarch
1 cup water
4 cups coconut milk
2 teaspoons vanilla
MAKE CAKE & WHIPPED CREAM FROSTING: Preheat oven according to directions on cake mix. Grease and flour two 8 or 9-inch round cake pans.
Prepare the cake according to the package directions, using 2/3 cup of the coconut milk, water, and egg whites.
When cakes are finished baking, cool and cut each cake horizontally into 2 layers. If your top layers are mound-shaped, cut them so they are flat. (If your layers aren’t flat, your filling/frosting will seep off the cake and you’ll have a mess.)
Soften gelatin in remaining 1/3 cup of coconut milk. Dissolve over hot water. Cool completely.
In a bowl, whip the heavy cream. Fold the gelatin mixture, sugar, and extract into the whipped cream. Chill frosting until it is of spreading consistency.
MAKE HAUPIA FILLING: In a small bowl, mix together the sugar, salt, cornstarch and water. Set aside.
In a saucepan, heat the coconut milk. When hot, add the sugar mixture. Cook, stirring constantly, until the mixture thickens. Remove from heat. Stir in vanilla and cool.
Chill the filling until it is of spreading consistency.
ASSEMBLE THE CAKE: Spread the Haupia Filling between each cake layer (spread it on pretty thickly, about 1/2" thick or so). You’ll have the following layers: cake, filling, cake, filling, cake, filling, cake.
Refrigerate assembled cake until set.
Frost entire cake with whipped cream mixture. Sprinkle coconut all over the cake sides and top.
Keep refrigerated until ready to serve.