Preheat the oven to 180°C. 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.
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.
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
Pour the chocolate mixture into the base. Return to the fridge and
leave to set for about one hour.
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. 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 two hours to set completely.