Grease a 12 hole muffin tin.
Cut out 12 large circles from the pastry using a mince pie cutter.
Lay the pastry circles carefully in the tin holes.
Place the tin in the fridge and leave to chill.
Preheat the oven to 200C, 400F, Gas 6.
Melt the chocolate in a heatproof bowl over a pan of simmering water.
Allow to cool a little then stir in the cream.
Beat the sugar and egg yolks together until creamy and stir into the chocolate mixture.
Remove the muffin tin from the fridge and add a teaspoon of toffee sauce to each tart base.
Fill the tarts with the chocolate mixture until close to the top but not overflowing.
Bake in the centre of the oven for around 20 minutes until the tops are set.
Carefully remove from the tin and allow to cool.
Dust with a little icing sugar and serve with cream.