Preheat your oven to 180°C (350°F). Grease and line two 9-inch round cake pans. In a mixing bowl, combine the flour, Dr. Oetker Coconut Pie Filling & Dessert Mix, and Dr. Oetker Baking Powder. Set aside.

In a separate bowl, beat the softened butter and caster sugar until light and fluffy. Add the eggs one at a time, beating well after each addition. Gradually add the dry ingredients to the wet mixture, alternating with milk, and mix until smooth.

Divide the batter evenly between the prepared pans and smooth the tops. Bake in the preheated oven for about 40 minutes or until a toothpick inserted into the center comes out clean. Allow the cakes to cool in the pans for 10 minutes before turning them out onto a wire rack to cool completely.

For the buttercream frosting, place the heavy cream and Dr. Oetker Coconut Pie Filling & Dessert Mix in a saucepan over medium heat. Stir continuously to prevent burning. Once the mixture comes to a boil and begins to thicken, continue to stir for 1 more minute. Remove from heat and stir well two separate times over a 5-minute period. Let it cool to room temperature.

In another bowl, beat the softened butter until smooth. Gradually add the cooled pudding mixture, beating until it achieves a smooth and creamy consistency. Spread one third of the buttercream frosting between the two cake layers, another third and over the top and the rest around the sides of the cake. Decorate with shredded coconut. Enjoy your deliciously rich and creamy coconut cake with buttercream frosting!