First up, preheat the oven to 200°C/180°C/Gas Mark 6, grease and line 2 x 8" round cake tins. Sift the flour and baking powder, stir both together and set aside. 

Using a stand mixer in a clean bowl, add the eggs and start beating the eggs on a low speed – gradually increasing the speed for maximum 4-5 minutes until frothy and fluffy - this makes the sponge more moist and soft. Now add the sugar slowly while beating the eggs and continue to mix for 3-4 minutes until all sugar dissolves. 

Add the flour and baking powder previously sifted, a few spoons at a time, and then fold it carefully in the sugar and egg mixture until everything is well combined together. Scrape the bottom of the bowl for any flour left. Divide the cake batter into the two prepared cake tins and bake for 28-30 minutes. Once the cake is baked check with a toothpick if it comes out clean. Loosen the sides of the cakes immediately then cool completely. 

In a medium size bowl, combine sweetened condensed milk, evaporated milk, and double cream, whisk together. Using a fork or skewer, poke holes across the cold sponge cake and pour on the milk mixture across the whole cake. Cover with plastic wrap and fridge for 1 hour to overnight.  

Whip the double cream with icing sugar until whipped. Carefully remove the cakes from their tins and pop into the freezer for  20-30 minutes - this helps frost them. Spread the whipped cream across the cake and sandwich the other cake sponge on top. Spread the remaining cream around the sides and top of the cake. 

Decorate the top of he cake in a moon crescent shape with the ground pistachios and rose petals. Pop the cake in the fridge to chill.

Chop the White Chocolate and add to a heat proof bowl with the vegetable fat. Melt together  a over double boiler or microwave. Flip a couple of baking trays upside down and smooth over the melted white chocolate mixture using an offset spatula. Pop into the fridge to harden.

Remove the chocolate trays from the fridge and leave to stand at room temperature for a couple of minutes. Working one edge at a time use a sharp knife to scrape the chocolate into curls - if the chocolate is too hard let it sit for at room temperature for a little longer and if it becomes too soft then place back in the fridge.