Put the biscuits and cocoa and slivered almonds into a food processor and blitz, Pour in the melted butter and mix till combined
Press the biscuit base into a rectangular loose bottomed tin and put in the fridge to chill.
Put the gelatine sheets into a jug of cold water and leave till just softened. Squeeze out excess water (if using powdered gelatine mix with enough water to make a paste).
Meanwhile put the raspberries, lemon juice, sugar, and butter into a microwave proof bowl and put into the microwave
Microwave on high for 2 minutes (1100 watts).Then take it out and give it a whisk to mix in the sugar and incorporate the butter. Add beaten eggs and whisk
Put into the microwave and blast at 30 second intervals whisking between each time. After the second or third whisking you should notice that the mixture is quite thick or starting to get thick and is hot.
Mix in the gelatin (paste or sheets) and whisk well. Strain the mixture through a fine sieve. Cool till room temperature. (or just chilled)
Beat the cream and fold through the Raspberry mixture.
Put whole raspberries onto the base of the tart in a line down the centre. Pour over the raspberry mixture and refrigerate overnight or up to 4 hours.