Begin by greasing 12 x 7.5cm loose bottomed fluted tins and place them to one side.
First make the base, place the digestive biscuits in a food processor and blitz until you have fine crumbs. Place the crumbs in a large bowl and put to one side.
Place the butter in a saucepan and melt, once melted add to the biscuit crumbs and stir to combine.
Take spoonfuls of the biscuit and butter mix and place them in the tins, using your fingers or the bottom of a glass to press the biscuit mix into the base of the tin and the sides. Continue until you have done all of the tins and then place them in the fridge to firm up.
Next make the chocolate filling, place 300ml of double cream in a saucepan with the cardamom pods and cinnamon stick. Bring the cream to a boil and then place to one side and leave to cool.
Place the chocolate in a bowl large enough to fit the chocolate and the cream.
Strain the cream through a sieve and then measure it back into a saucepan, top up the cream to 300ml if necessary. Heat the cream until just at a boil, wait a couple of minutes and then pour the cream over the chocolate and stir until completely melted.
Add the chocolate a piece a time and stir to combine, when the butter is fully incorporated, spoon the chocolate filling into the chilled biscuit cases, be sure to stop a little before the top of the case, so that you have room for the glaze. You will have more chocolate filling than you need, but the excess can be put into shot glasses or similar sized cups and chilled in the fridge to make a rich delicious treat.
Leave the chocolate filling to set in the fridge for a couple of hours and make the chocolate glaze.
Finally make the dark chocolate glaze, soak the gelatine in a bowl of cold water for a few minutes until soft. Squeeze out the excess water.
Put the water and sugar in a saucepan, bring to the boil, then continue to simmer over a low heat for 2-3 minutes. Add the sifted cocoa powder and the cream, mix thoroughly.
Bring back to the boil and simmer for 4-5 minutes. Take the pan off the heat and add the pre-soaked gelatine and stir until dissolved. Strain then leave to cool.
Take the tarts and gently prize them out of the tins and place them back in the fridge.
When the glaze is around 30C in temperature, take spoonfuls of the glaze and pour them over the chocolate tart to lightly cover the surface, you really won’t need a lot per tart.
Finally place a Guylian shell on top before the glaze sets and return the tarts to the fridge for the glaze to set.
When serving, take the tarts out of the fridge 15 minutes before eating to allow them to come up to room temperature. They will keep in the fridge in an airtight container for 2-3 days.