Spoon a little ganache onto the middle of the cake board and place the first layer of sponge on top.
Fill a piping bag with 7-8 tablespoons of ganache.
Pipe a ring around the edge of the cake, making a barrier to prevent any of the raspberry filling from spreading out of the sides.
Spoon 2-3 tablespoons of the raspberry filling into the middle of the ganache ring you have piped and spread out until even.
Place the next sponge layer on top and repeat, using the last of the raspberry filling between the 4th and 5th layers.
Spoon half of the ganache on to the top of the cake.
Using a large angled spatula, smooth out the ganache until it is flat on top, gently easing the excess ganache down the sides.
Smooth out the ganache around the sides of the cake, adding extra ganache where needed, until it is smooth and completely covered.
Place the leftover ganache into the fridge until it has set firm.
Using a teaspoon or melon baller, spoon a small amount of the ganache and roll into a ball.
Roll the ball in cocoa powder and place to one side.
Repeat until you have used all of the leftover ganache.
Add a little shimmer to the truffles by using the gold lustre dust.
Mash the raspberries before beating together with the butter and icing sugar until smooth.
Add the buttercream to a piping bag which has a star tip attached.
To decorate the cake, place the truffles, and raspberries in a crescent shape on top of the cake.
Fill in any gaps by piping a little of the buttercream in star shapes - hold your piping bag vertically, apply pressure until a star shape has formed, stop piping and lift up immediately.
Finish by adding edible flowers and sprinkles.