First off, start making the macaroon layer, take 1/2 the sugar and the whites from 2 of the eggs and combine with the marzipan in a bowl with the icing sugar. Once completely dissolved, lightly grease a rough size on greaseproof paper and bake for about 30 minutes.
Melt half the chocolate with equal amounts of butter in the microwave or over a hot water bath. Once completely melted, take off the heat, add half the caster sugar and stir until dissolved. Scrape the vanilla sticks and add to the mixture.
Mix the rest of the eggs with the rest of the caster sugar in a different bowl and when reasonably combined add 1/2 to the chocolate mixture a little bit at a time, stirring while you do.
Whisk the rest of the egg and sugar mixture until turning a pale yellow and fold in the mix. Lastly fold in the flour and the baking powder and put to rest.
Prepare the gelatine as the packet suggests.
In a small pot combine dark sugar, 1/4 pint of water and 1/2 the raspberries and the blackberries and the southern comfort (other liquors can be used as well, make sure it adds flavour) and bring to a light boil, maintain temperature for about 5 minutes until sugar is dissolved and moist, or all of the alcohol is boiled away. Cool the mixture and run it through a blender, then pass it through a sieve to get rid of any large kernels. Finally add the rest of the raspberries and the blackberries and coat them with the mixture and add the gelatine as per the instructions on the pack (must be sufficiently cooled) and then leave in the fridge until you finish baking the rest.
Pour half the chocolatey dough into a mould roughly the size of the macaroon layer already made, and repeat with the rest so you get 2 equally sized chocolate layers. The chocolate brownie depending on thickness needs to bake for about 25-35 minutes. They should be done when inserting a knife into the middle, it comes up greasy but with no chocolate on it.
Now with all your pieces baked (be careful they don't break as they are quite brittle), start first with a layer of the brownie, add onto this the mint chocolate biscuits crushed or cut into small pieces, coat the entire layer with it and cover the edges with the jam so the cake sticks. Add the macaroon layer on top of this and cover with the rest of the jam. Put the last brownie layer on top. Melt the 4/5 of the remaining chocolate over a hot water bath or in the microwave and coat the cake with it. Cut the rest of the chocolate up and sprinkle it on the cake together with the pecans. If you're feeling fancy you can coat the pecans in honey first as it looks better on the finished cake.
If you want to make the cake look perfect shape wise, cut off the edges that might be a bit tougher than the rest before coating it with the chocolate.