Ube-Macapuno Cake

Preheat the oven to 325 degrees F (165 degrees C). Line the bottom of three 9-inch round pans with parchment paper, but do not grease.

Make the ube cake: Mix flour, baking powder, and salt together in a large bowl; set aside. Place grated ube in a large bowl. Combine 3/4 cup milk and 1 teaspoon vanilla; gradually blend into ube until smooth. Blend in egg yolks, corn syrup, and oil. Beat in flour mixture until smooth; set aside.

Combine egg whites and cream of tartar in a large bowl; beat with an electric mixer until foamy. Gradually add sugar, then red and blue food coloring, continuing to beat until stiff peaks form. Fold 1/3 of the whites into batter, then quickly fold in remaining whites until no streaks remain. Pour batter into prepared pans.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 30 to 35 minutes. Invert pans on a wire rack and let cool upside down. When cool, run a knife around the edges to loosen cake from the pans. Spread coconut preserves onto the cooled cake layers; stack layers on a cake stand or serving plate.

Make the buttercream: Combine evaporated milk and 3/4 cup sugar; set aside. Combine butter and sugar in a large bowl; beat with an electric mixer until smooth and creamy. Beat in food coloring, one drop at a time, until the desired tint is achieved. Frost top and sides of cake with buttercream.