Preheat your oven to 350°F (175°C). Grease and flour a 9-inch cake pan.
In a mixing bowl, combine the flour, sugar, baking powder, and salt.
In another bowl, mix the ube halaya, vegetable oil, coconut milk, ube extract, and eggs until well combined.
Gradually add the wet ingredients to the dry ingredients, mixing until just combined.
Pour the batter into the prepared cake pan and bake for 45 minutes or until a toothpick inserted into the center comes out clean.
Let the cake cool completely before frosting.
For the frosting, whip the heavy cream and powdered sugar until stiff peaks form. Fold in the macapuno strings.
Spread the frosting over the cooled cake. Serve and enjoy!