In a medium saucepan, stir together the milk and sugar over medium heat bring to a boil.

While the milk is coming to a boil, in a mixing bowl, whisk together the egg yolks and egg.

Stir the cornstarch into the eggs until smooth.

Whisk 1/3 cup of the hot milk into the egg mixture. This will temper the eggs and stop them from curdling or cooking.

Add the rest of the milk slowly to the egg mixture while whisking.

Return the mixture to the saucepan over low heat stir the mixture constantly stirring so the eggs don't burn on the bottom of the pan, until thickened.

Once the custard has thickened, remove from the heat.

Stir in the the vanilla and lemon zest, mix until well incorporated.

Transfer the custard to a heat-proof dish and put plastic wrap directly on top of the custard to prevent a skin. Cover with a lid and refrigerate for at least 2 hours until set.

Preheat oven to 375 degrees F.

Line a baking sheet with parchment paper.

Flour a clean surface and roll out pastry to 14 x 12 inches.

Carefully transfer the pastry to the baking sheet and prick holes all over with a fork.

Bake for 15 minutes until light golden.

Remove the pastry from the oven and place another sheet of parchment paper over the pastry and weigh down with another baking sheet.

Bake for a further 15 minutes until golden brown.

Using 2 spatulas, transfer the warm pastry onto a cutting board and cut into a 12 x 9 inch shape (the pastry will have shrunk). Then cut in half to get 2, 6 inch pieces. Then cut those into thirds so you end up with 6 each of 6 x 3 inch pieces. Allow the pastry to cool completely.

Once the cream is cooled, transfer to a piping bag (or ziptop bag and snip off the corner).

Place 1 pastry piece into a serving plate and arrange 8 raspberries around the edges. Pipe a little cream between each. Lay another layer of pastry on top, repeat with the raspberries and cream.

Lay a final layer of pastry on top and sprinkle with grated chocolate and 1 raspberry.

Repeat the layering process for the 2nd Napoleon.