Heat oven to 160C/140C fan/gas 3. Grease and line the base of 2 x 18cm round sandwich tins.
Start with the chocolate sponges. Put all the ingredients in a bowl and beat with an electric whisk until the mixture comes together smoothly. Working quickly, weigh the batter, then spread exactly half in each tin. Bake for 30 mins – when you poke a skewer into the middle, it should come out clean. Cool in the tins for 15 mins, then carefully turn out onto wire racks to finish cooling while you make the raspberry-rose sponges.
Clean the tins, then grease and line as above. Whizz the freeze-dried raspberries and flour together until no lumps of raspberry remain. Tip into a mixing bowl, add the butter, sugar, eggs, almonds, rose water and yogurt, and beat together as above. When smooth, beat in a little pink food colouring bit by bit until you get a nice colour – it will fade a bit during baking. Weigh, divide between the tins and bake and cool as above.
Once cool, gently cover and chill the sponges for 30 mins – this will make cutting them easier and neater.
Unwrap the sponges and, if they have domed in the centre, trim to flatten. Cut a 12cm-diameter circle out of the centre of each sponge using a biscuit cutter or paper template. Then cut a 6cm-diameter circle from the centre of your 12cm sponge. From each sponge, you should end up with a 6cm circle, a 12cm ring and an 18cm ring. Swap the middle rings of the chocolate sponges with the middle rings from the raspberry-rose sponges, and fit the cut pieces back together. Handle the sponges very gently to avoid cracking the edges too much.
Heat the jam to melt, then sieve to remove the seeds. Generously brush some over one of the sponges and top with an alternating sponge. Repeat to stack up all the layers. Sit the cake on a serving plate or cake stand.
Break the chocolate into a heatproof bowl with the cream and butter. Set over a pan of barely simmering water so the bottom of the bowl doesn’t touch the water, and very gently melt together. Cool until slightly thickened and more spreadable, then spread all over the cake to finish. Don’t return to the fridge – this cake keeps for two days at room temperature – and tastes better the day after assembling.