Place the coconut milk in a small pan and bring to the boil, remove from the heat and stir in the desiccated coconut then the vanilla and coconut extracts. Set aside for about half an hour until the mixture has cooled and the desiccated coconut has softened.
Preheat the oven to 180C/350F/gas mark 4, grease three 15cm/6in round cake tins (or two 20cm/8in ones) and line the bases and sides with baking paper.
Beat the butter and sugar together with an electric mixer until light and fluffy. Beat in the eggs one at a time.
In a separate bowl, sift together the flour and baking powder. Fold it into the butter mixture a little at a time, alternating with spoonfuls of the cooled coconut mixture.
Divide the batter between the prepared tins and level it, bake in the middle of the oven for 20-25 minutes, until risen and golden and a skewer inserted into the centre comes out clean or with a few moist crumbs.
Leave the cakes to cool in their tins.
Whisk together the milk and flour in a small pan until smooth. Place over a medium-low heat and whisk constantly until the mixture is very thick and paste-like. Scrape into a bowl, cover with clingfilm directly on the surface and refrigerate until completely cold.
Once the flour mixture is cold, place the butter and sugar in a large bowl or the bowl of your stand mixer and whisk on high speed for a good few minutes until extremely light and fluffy. Whisk in the vanilla and salt.
Whisk in the flour mixture a tablespoon at a time, whisking well after each addition, until it has all been mixed in and the buttercream is completely smooth, it should almost have the consistency of whipped cream.
Finally whisk in the freeze dried raspberry powder.
Place one of the cake layers on a cake stand or serving platter. Put a large dollop of the buttercream in a piping bag fitted with a large round nozzle.
Spread a thin layer of buttercream over the first cake layer then pipe a ring of buttercream around the edge (this acts as a dam to stop the lemon curd from leaking out.). Fill the middle with a couple of heaped spoonfuls of lemon curd.
Place another cake layer on top and press down very gently. Repeat the same process as the previous layer then place the final cake layer on top; upside down so that the top of the cake is perfectly flat.
Spread a very thin layer of buttercream all over the cake then place it in the fridge for half an hour to firm up a little.
Spread another, thicker layer of buttercream over the cake; using a leveler or palette knife to get it as smooth as possible.
Take a handful of crushed freeze dried raspberries and carefully press them around the bottom of the cake. Repeat until you have gone all the way round. Top the cake as you like with freeze dried raspberries, desiccated coconut, mint sprigs and dried rosebuds. Store in an airtight container for up to five days.
I used three 15cm/6 inch tins for the cakes but you can use two 20cm/8 inch tins if you prefer.