Mix the raspberries into a sauce pan with the sugar.
Bring to boil for 4-5 minutes. The raspberry seeds contain pectin which is a natural gelling agent.
Tip the cooked berries into a sieve over a bowl, then once all of the juice has drained off, firmly work the pulp through the sieve with a wooden spoon until you are left with just the seeds.
Mix the egg yolks, flour and sugar into a large bowl.
Mix until it has a smooth consistency.
Put the mixture and the raspberry coulis into a saucepan and swirl together.
Cook over moderately low heat, whisking frequently. Whisk until the cream is thick enough to hold the marks of whisk and the first bubble appears on the surface.
Let it cool for 10min.
Stir in the margarine.
Let it cool for another 10 min
Put the clinging film on the pastry cream and refrigerate it.
Now, lets start with the puff pastry.
Pre-heat your oven to 200C.
On a lightly floured surface, gently roll out the puff pastry dough into an elongated rectangle about 3mm thick.
Transfer the dough to a baking pan (or pans) lined with parchment paper and pierce the dough all over with a fork.
Cover the dough with a grill to weigh down the dough as it bakes.
Bake for 20 minutes, or until the dough is deep golden brown and very crisp.
Transfer the baked pastry layer and let it cool completely.
With a sharp knife, cut the dough into 3 equal-sized pieces.
Add the mixture into a piping bag fitted with a round tip.
Start by distributing the pastry cream over one layer of baked puff pastry.
Put some raspberries and press them lightly down by half in the cream. Add some pastry cream in-between the row of raspberries
Top with another layer of dough, pressing gently to adhere it to the pastry cream below. Spread the remaining pastry cream and raspberries over the second layer of pastry.
Top with the third layer of pastry and again press down gently.
Use a spatula or a knife to smooth the sides of cream.
Make the royal icing by mixing the egg whites, icing sugar, lemon juice and food coloring until it’s very smooth and glossy.
Immediately pour the royal icing over the top layer of pastry and spread it evenly over the entire surface.
Finish garnishing with some raspberries.
Your raspberry millefeuille is now ready! You can enjoy it with your valentine if you are lucky or have it all to yourself!