Preheat the oven to 350°F. Lightly grease three 8 inch round cake pans and line with parchment, set aside.

In the large bowl of a stand mixer with the paddle attachment fitted add the granulated sugar, flour, baking powder and salt. Turn the mixer to a low speed and mix to combine.

Add the butter and increase the mixer speed to medium. Beat for 3 minutes or until the texture of the ingredients looks like damp sand.

Turn the mixer to its lowest speed and gradually pour in the heavy cream, buttermilk and vanilla extract.

Turn the speed to medium and beat the ingredients together for 2 minutes. The cake batter will look very thick.

Stop the mixer and thoroughly scrape down the sides and bottom of the mixing bowl. Turn the mixer back on and mix on a medium speed for 30 seconds.

With the mixer on its lowest speed add the egg whites in thirds, beat for 20 seconds after each addition. At this stage the cake batter should look silky smooth. Do not over mix.

Divide the cake batter between the three prepared pans. Bake in the preheated oven for 20-22 minutes or until the cakes are a very pale golden color, shrinking away slightly from the edges of the pan and feel springy when touched with your finger. A toothpick inserted into the middle should come out clean.

Leave the cakes to cool in the pan for 10 minutes then invert onto a wire cooling rack to completely cool.

To a large heatproof, microwave safe bowl, add the chopped white chocolate. Melt it in 30 second increments in the microwave at 50% power, stirring well each time until fully melted. Set aside to cool.

In the large bowl of a stand mixer fitted with the paddle attachment, add the soft butter. Beat on a medium speed for a few minutes until the butter is creamy.

With the mixer on its lowest speed, gradually add the powdered sugar. When the sugar is incorporated into the butter increase the speed to high and beat for 2 minutes. Turn the mixer off and scrape down the sides of the bowl.

Add the cooled, melted chocolate and beat on a medium speed for 2 minutes.

Lastly, add the heavy cream (or milk if using) and beat again for 1 minute or until the buttercream is very light and fluffy. Transfer one third of the buttercream to a piping bag and cut the end off with a pair of scissors.

Place a cooled cake layer on a serving plate or cake stand.

Pipe a ring of buttercream around the outside edge of the cake. Fill the inside with ¼ cup raspberry preserves then pipe a layer of buttercream on top of the raspberry preserves.

Place the next cake layer on top and press the layers gently to sandwich them together.

Pipe another ring of buttercream around the outside edge of the cake. Fill the inside with the remaining ¼ cup raspberry preserves then pipe a layer of buttercream on top of the raspberry preserves.

Place the last layer on top of the cake and use an offset spatula to spread a thin layer of buttercream on top of the cake and around the sides. This is your crumb coat - at this stage, to make decorating easier, place the entire cake into the refrigerator for 30 minutes.

After 30 minutes, spread the remaining buttercream in a thick layer on the top and around the sides of the cake. Use a cake scraper to smooth it out evenly.

Add fresh raspberries to the outside edge of the cake and scatter white chocolate curls on top.

Slice, serve and enjoy!