• Butter or spray with non stick spray a 9in/ 23cm tart tin with a removable base. Preheat oven to 350°F/180°C

Make pastry

• Beat butter and sugar together until combined. Add egg yolk and beat in thoroughly. Stir in flour until it form a soft dough. Don't over mix.
• Roll out the dough between two sheets of non stick baking paper that has been floured. While rolling check that the dough isn't sticking. If so, sprinkle with extra flour.
• The dough should be a about ¼inch or 6mm thickness. You will have a bit of pastry leftover - check in the "recipe notes" for tips on what to do with the extra pastry.
• Use the pastry to line the tart tin.
• If you have time chill for 30 minutes.

Make the filling

• Beat butter and sugars until pale and fluffy.
• Add in eggs, ground hazelnuts and flour. Beat to combine.
• Stir in melted chocolate.
• Spoon into pastry case and smooth out the top.

Prepare the pears.

• Peel pears. Cut in half length ways and scoop out the core. Turn the halves onto their cut side and use a sharp knife to cut parallel the long way down the pear leaving a small amount attached at the tip. Make the slices quite thin that way they will cook through. Repeat with remaining pear halves.
• Fan out the pears and arrange on the tart. Press down lightly.
• Bake the tart for 45 minutes or until firm and the pastry is golden brown.
• Leave to cool. Dust with icing sugar to serve.