Last summer I made quite a few chocolate tarts. They are killer dense and rich and actually very easy. All you do is blind bake your pastry and then filll with molten chocolate before letting it set. So you don't even need to do the whole back-in-the-oven to set bit. After a delicious run-in with a new orange and pistachio chocolate bar, I took it upon myself to emulate the moorish bar in a dense and decadent chocolate tart.
For the pastry I followed a recipe from Tamasin Day-Lewis' book, 'Art of the Tart' which is a great fall back for understanding each type of pastry tart and all the multifarious incarnations. For the chocolate filling, heat double cream until it is nearly at boiling point. Pour this over the same amount of broken chocolate and flavour with salt and orange zest. Pour this into the baked pastry case and scatter over crushed pistachio nuts. It's basically like making a massive truffle. Leave the tart to cool before refrigerating to fully set.