How to Make It
To prepare filling, combine raspberries, 1/3 cup sugar, 2 tablespoons water, and 1/8 teaspoon salt in a saucepan; bring to a boil. Cook over medium heat 5 minutes, stirring frequently until berries break down. Combine cornstarch and liqueur; stir with a whisk until smooth. Add cornstarch mixture to raspberry mixture, stirring with a whisk; return to a boil. Cook 1 minute or until very thick, stirring constantly. Spoon mixture into a bowl; cover and refrigerate until needed.
Preheat oven to 350°.
To prepare cake, coat 3 (8-inch) round metal cake pans with baking spray, and line bottoms of pans with wax paper. Coat wax paper with baking spray; set prepared pans aside.
Weigh or lightly spoon flours into dry measuring cups; level with a knife. Combine flours, baking powder, and salt in a bowl; stir with a whisk. Place 1 1/4 cups sugar, oil, butter, and vanilla in a large bowl. Beat with a mixer at medium speed for 5 minutes or until fluffy. Add coconut water; beat at low speed 1 minute or until combined. Add flour mixture; beat at low speed 1 minute or until well combined.
Place 6 egg whites in a large, clean bowl. Beat with a mixer at high speed until medium peaks form using clean, dry beaters. Add 1/4 cup sugar, 1 tablespoon at a time; beat 1 minute. Stir one-fourth of egg white mixture into batter; gently fold in remaining egg white mixture. Divide batter evenly among prepared pans. Bake at 350° for 19 minutes or until a wooden pick inserted in center comes out clean. Cool in pans on a wire rack for 10 minutes. Remove from pans; cool completely on wire rack.
To prepare frosting, place 3 egg whites and cream of tartar in a large bowl; beat with a mixer at high speed until medium peaks form using clean, dry beaters. Combine 1/2 cup sugar, 3 tablespoons water, and 1/8 teaspoon salt in a saucepan; bring to a boil. Cook, without stirring, until candy thermometer registers 250°. With mixer on low speed, pour hot sugar syrup in a thin stream down the side of mixing bowl. Gradually increase speed to high; beat 3 minutes or until thick and cool.
To assemble cake, place 1 cake layer on a serving plate; spread with half of filling (about 1 cup), leaving a 1/2-inch border. Top with another cake layer, and spread with remaining filling, leaving a 1/2-inch border. Top with remaining cake layer. Spread frosting over top and sides of cake. Gently press coconut flakes into sides of cake.