Break the pastry into chunks and drop
into a food processor. Drizzle over the
vanilla paste and pulse until the vanilla is
speckled through the pastry (the extract
should be completely absorbed). Tip out
onto a floured surface, bring together
into a ball, then roll out to line a 23cm
tart tin (leave any overhanging pastry as
you will trim this away when the tart is
baked). Chill for 30 mins.
Heat oven to 200C/180C fan/gas 6. Line
the pastry with greaseproof paper. Fill with
baking beans, bake blind for 15-20 mins,
then remove the paper and beans and
bake for 5-10 mins more until pale golden.
Carefully spread caramel over the base
and set aside while you make the filling.
Lower oven to 180C/160C fan/gas 4.
Melt the chocolates in a bowl over a
pan of barely simmering water, then stir
in the melted butter. Whisk the eggs,
yolks and sugar together with an electric
whisk in a large mixing bowl for 10 mins,
until pale and thick enough to leave a trail
when the beaters are lifted up. Fold in
the melted chocolate with a large metal
spoon, then scrape into the tin.
Bake for 20-25 mins – the surface should be set
and puffed but still with a slight wobble.
Cool, then chill for at least 3 hrs or
overnight, before dusting with icing
sugar and serving.