Beat the eggs with the sugar and flour until white and fluffy.
Place the milk in a bowl and bring to the boil. Once boiling, pour the milk gently into the egg mixture and mix well. Return to the pan and simmer over a medium heat for 3 minutes. Pour the crème pâtissière into a baking dish, cover with cling film and place in the fridge to cool for 1 hour.
Beat 4 egg yolks with 100g of sugar. Add the ground almonds the melted butter and mix well.
Remove the crème pâtissière from the fridge and whisk. Add the frangipane mixture and mix well. Place the mixture into a piping bag.
Whisk the remaining egg yolk with a little water. This will be used to glaze the pastry.
Cut the puff pastry sheets into two large discs. Brush the beaten egg around the edges of one of the pastry discs. Cover the pastry with a 1cm layer of frangipane and add your 'fève' or lucky charm. Top with the second puff pastry round and firmly press the edges together. Score the top with the blade of a knife, making a diamond pattern by criss-crissing the pastry. Brush with the beaten egg and then chill in the fridge for 30 minutes. Preheat the oven to 180°C.
Brush again with the beaten egg then transfer to the oven and bake for 40 minutes.
Allow to cool before serving.
«Try making this recipe using ground almonds or hazelnuts instead of ground almonds.»