1. Sieve 225g flour and a pinch of salt together. Rub in 125g of cold butter, cut into small pieces, and rub in until the mixture resembles breadcrumbs.

2. Stir in 25g caster sugar, 2 - 3 tbsp sieved cocoa powder and mix together.

3. Beat 1 egg yolk with the water and mix into the dry ingredients.

4. Add more water, as required to make a firm dough.

5. Knead lightly until smooth, and then wrap in cling film and put in the fridge for 30 minutes.

6. Use the pastry to line a 9 inch round tart tin and bake blind in a hot oven 200°c / 400°f / Gas Mark 6 for 10 to 15 minutes, removing the baking parchment and baking beans and returning to the oven for a further 5 minutes.

7. Remove from the oven and leave to cool completely.

8. Sieve the remaining flour, cinnamon, 1/4 tsp of salt into a pan an stir in the 125g light brown sugar, and the milk.

9. Break the chocolate into pieces and add to the pan.

10. Heat gently until the chocolate is melted, stirring all the time.

11. Mix to ensure that the chocolate and milk are thoroughly blended.

12. Increase the heat and cook for another 10 minutes, stirring all the time.

13. Remove the pan from the heat. Beat the remaining 3 egg yolks with a little of the chocolate mixture before slowly pouring the eggs back into the saucepan, stirring rapidly.

14. Continue cooking over a low heat until the mixture is thick and creamy. Do not let it boil.

15. Remove from the heat and stir in the remaining butter and vanilla essence. Pour into the cooled pastry case.

16. Whisk the egg whites until stiff but do not dry.

17. Whisk in 50g caster sugar until the mixture is thick and glossy.

18. Fold in the remaining caster sugar and pile the meringue on top of the pie.

19. Bake for 10 minutes at 200°c / 400°f / Gas Mark 6 or until the meringue is crisp and lightly browned.

20. Chill before serving and decorate with crystallised rose petals.