Pastry cream:

 Line a quarter-sheet tray with a silicone mat. Set aside.

 Add the ginger and milk to a small saucepan. Simmer over low heat for 5 minutes. Remove from heat and allow the ginger to steep in the cream for 30 minutes.

Remove and discard the ginger. Re-weigh infused cream. If necessary, add additional cream to “top up” to 240 milliliters (1 cup).

Return to saucepan and whisk in half of the sugar. Warm mixture over medium heat until steaming. (Do not boil).

Meanwhile, whisk together egg yolks, flour, cornflour, vanilla bean paste, and remaining sugar in a large bowl.

Pour the hot milk gradually into the egg mixture in a thin stream, whisking well after each addition. Be careful not to pour too quickly or add all of the milk at once.

Next, pour the entire mixture back into the saucepan. Cook over medium-low heat, stirring continuously with a whisk or spatula. Mixture will begin to thicken as it cooks.

Once thickened, bring pastry cream to a low boil. Boil for 1-2 minutes, stirring continuously. Remove from heat.

With a clean spatula, transfer pastry cream to prepared tray, and spread evenly over the surface.

Wait until the pastry cream stops steaming, then cover with clingfilm/plastic wrap. Use your hands to “pat down” the film. (Make sure the plastic directly touches the pastry cream—this prevents a rubbery “skin” from forming on top.)

Allow pastry cream to cool to room temperature, then transfer to the refrigerator until ready to use.

Pastry:

Preheat oven to 400° F / 205° C. Line a 12 x 14-inch baking tray with parchment.

On a silicone rolling mat, use a rolling pin to roll the pastry to 1/8-inch thickness. Trim edges to form a 10 x 13-inch rectangle.

Lift the rolling mat and flip the pastry onto the  prepared tray.

Top with a second sheet of parchment, then add a second baking tray on top.

Bake in preheated oven for 20 minutes. Remove top tray and parchment and bake for 5 minutes more, or until deeply golden brown. (Keep a close eye on the oven—don’t let the pastry burn!)

Sit tray on a wire rack and allow pastry to cool completely before assembling the mille feuille.

Assembly:

Remove clingfilm/plastic wrap and scrape pastry cream into a clean mixing bowl, or the bowl of a stand mixer. Mix on high speed for 30-60 seconds, or until smooth and creamy.

Transfer to a piping bag fitted with 1/2-inch round tip.

Place pastry on a chopping board. With a sharp chef’s knife, slice pastry into 12 rectangles, each about 2 x 4 1/2 inches in size.

Pipe four of the rectangles with dollops of pastry cream, alternating with sliced pears.

Place a second rectangle of puff pastry on top.

Pipe with remaining pastry cream, alternating with the blackberries.

Top with remaining puff pastry rectangles.

Finish with a dusting of confectioner’s sugar.

Garnish with additional berries, fresh herbs, or a dollop of whipped cream. Serve immediately.