Ube, also known as purple yam, has exploded in popularity here in the U.S. and the rest of the world. It's actually difficult to describe the taste. It is more like an essence similar to vanilla. The resulting cake is light and not overly sweet. The addition of macapuno adds to its sweetness and texture.
Preheat oven to 350 degrees. Prepare three 8 inch round pans by spraying with baking spray.
In a large bowl, sift flour, baking powder, ¾ cup sugar and salt and mix until well combined. In a separate bowl combine the egg yolks, oil, milk and ube (as well as ube extract and violet gel paste to enhance color). Add dry ingredients to the wet ingredients beating on lowest setting until just combined. Set aside.
In a separate bowl, whisk egg white on high speed until frothy. Gradually add ¾ cup sugar and cream of tartar and beat until stiff peaks form. Gently fold in egg whites into the ube mixture until well combined
Divide batter into prepared pans. Bake for about 30 minutes or until toothpick inserted in the cake center comes out clean. Allow to cool for about 5 minutes and immediately transfer to wire rack
Place egg whites, sugar and salt in a heatproof mixing bowl over a pan of simmering water. Whisk gently and constantly until sugar is dissolved and egg whites are hot, about 4 minutes. Remove from heat.
Whisk on mixer on medium/high setting to stiff peaks, about 5 minutes.
Beat in butter in small batches. It will look runny at first. Continue beating until buttercream comes together. Add vanilla and beat until incorporated.
Place a cake layer on a cake board and spread a thin layer of buttercream and coconut strings. Place the 2nd cake layer on top and spread a thin layer of buttercream and coconut strings. Place the 3rd layer on top.
Crumb coat the cake by spreading a thin layer of the buttercream on the top and sides. Chill in refrigerator for about 30 minutes.
Once crumb coat is set, cover the cake with the rest of the buttercream.
Decorate the top and sides with the coconut strings and chill again to set.
To serve, transfer to a cake platter or cake stand, slice and enjoy!!