Whisk the egg and sugar together then mix in the cream and vanilla extract. Make a hole in the centre of the pie and pour in the custard, put back into the oven for a further 20-30 minutes or ...

Bake the tarts in the oven for about 25 minutes - you may need to turn the temperature down to 180C/350F/Gas 4 for the final 10 minutes. You are looking for a very slight dome on the custard ...