Step 1

Preheat the oven to 180°C/gas Spread both the pecans and hazelnuts out on a baking tray and roast for about 15 minutes until nicely golden. Remove and set aside to cool.

Step 2

Place half the nuts in a food possessor and blitz to a fine powder, then put into a bowl. Blitz the rest of the nuts to a rough crumb, then mix with the powdered nuts. Add the melted butter and a pinch of sea salt and stir to combine. Tip the mixture into a 23cm loose-bottomed tart tin and press firmly up the sides and into the bottom of the tin. You want the base to be crunchy and quite thin, rather than a thick crust. Chill in the fridge while you get on with the filling.

Step 3

Put the mascarpone, double cream, white chocolate, vanilla and cardamom into a pan and warm over a low heat, stirring all the time to let the chocolate melt, then add a pinch of salt and remove from the heat.

Step 4

Pour the chocolate mixture into the base. Return to the fridge and leave to set for about 1 hour.

Step 5

Put the raspberries into a sieve suspended over a bowl. Use a spoon to press the raspberries through the sieve, leaving the seeds behind in the sieve.

Step 6

Once done, take the nearly-set tart out of the fridge and use a teaspoon to dot blobs of the raspberry purée over the tart. Turn the teaspoon over and drag the dots a little to create a pretty, swirled effect. Return to the fridge for another 2 hours to set completely.