Ingredients

Step by step

1. Preheat the oven to 180°C, fan 160°C, gas 4. Grease a 23cm fluted tart tin with oil and line the base with a circle of baking paper. Melt the butter in a small pan over a low heat. Meanwhile, put the digestive biscuits in a large food bag, seal and bash to fine crumbs. (Alternatively, whizz to crumbs in a food processor.) Tip the biscuit crumbs into a large bowl and stir through the melted butter until coated. Press the crumbs into the base and up the sides of the prepared tart tin. Bake for 15 minutes, then use the back of a spoon to gently push down the biscuit base where it has puffed up. Leave to cool completely.

2. Meanwhile, set a sieve over a bowl and line the sieve with two sheets of kitchen roll. Tip in the ricotta, then wrap it with the kitchen roll and gently squeeze out the excess liquid. Leave to drain further while the base cools.

3. To make the filling, put the mascarpone, drained ricotta, sifted icing sugar, pistachio crème and vanilla in a large mixing bowl. Stir with a spatula until combined and an even pale-green colour. Pour in the double cream and incorporate with a balloon whisk. Continue to whisk for a further 1-2 minutes until holding soft peaks. Spoon the filling into the cooled biscuit base and smooth over the top. Sprinkle the chopped chocolate and pistachios around the edge of the tart. Chill in the fridge overnight.

4. To serve, carefully release the tart from its tin onto a flat serving plate or board, then cut into slices to serve.