1-First Step: Prepare the Crème Pâtissière (Vanilla Custard)Begin by heating 1 litre of full-fat milk with 1/4 cup caster sugar, vanilla seeds, and the reserved pod in a saucepan. Heat until just below boiling, then remove from heat and cover. Let it steep for 10 minutes to infuse the vanilla flavor deeply into the milk. Meanwhile, in a separate bowl, whisk 120g (6-7 large) egg yolks plus 1 whole egg with the rest of the caster sugar until the mixture becomes pale and combined.

2-Second Step: Combine Egg Mixture and MilkAdd 7 tablespoons of cornflour to the egg mixture and whisk until smooth, ensuring no lumps form. Temper the egg mixture by slowly pouring in half of the warm vanilla-infused milk, whisking constantly. Then combine it all and return to the saucepan.

3-Third Step: Cook the CustardPlace the saucepan over medium-low heat and stir gently yet continuously to avoid burning or curdling. Watch closely as the custard thickens and large bubbles begin to form. Continue whisking for another 20 seconds to ensure the custard is completely set. Remove from heat, then stir in 50g cold, cubed unsalted butter until fully incorporated. Strain the custard through a fine sieve to eliminate any vanilla bean fragments.

4-Fourth Step: Cool and Chill the CustardPour the custard into a bowl and cover directly with cling film, pressing it against the surface to prevent skin formation. Allow it to cool at room temperature for 3 to 4 hours, then refrigerate for 12 to 24 hours. This step intensifies the flavor and firming of the custard, essential for flawless slices.

5-Fifth Step: Prepare the Pastry CrustIf using puff pastry, choose slightly thawed sheets and cut a 20 cm circle for the base. Cut strips approximately 5.5 by 25 cm for the sides and keep these pieces frozen to maintain shape. Butter and line an 8-inch springform pan with baking paper on the sides. Fit pastry strips overlapping by 1 cm around the sides, sealing edges with water, then place the base and seal seams. Prick the base about 30 times with a fork to prevent puffing in the oven. Freeze the assembled crust for 2 to 4 hours to maintain structure.For shortcrust pastry, mix flour, icing sugar, ground almonds, and cold butter until the mixture resembles coarse sand. Add 1 egg yolk and cold water as needed to form a dough ball, chill for 30 minutes, roll out, and line the buttered pan.

6-Sixth Step: Blind Bake the CrustPreheat the oven to 220°C (430°F) or 200°C fan. Line the crust with parchment paper and fill it with baking beads or large dried beans to keep it flat. Bake for 25 minutes, then remove the paper and beads and bake another 5 to 10 minutes until golden and crisp. Cool for 10 minutes before filling.

7-Seventh Step: Assemble and Bake the Flan PatissierLower the oven temperature to 200°C (390°F) or 180°C fan. Whisk the chilled custard to loosen it, and pour into the pastry shell, filling up to 1 cm below the rim. Smooth the top with an offset spatula. Brush gently with a whisked egg yolk to achieve a glossy finish.Bake for approximately 65 minutes, rotating the tray 180° at 45 minutes to ensure even cooking. The custard should be set but slightly wobbly in the center. Use the broiler briefly if you want a caramelized surface, but watch carefully to avoid burning. Cool at room temperature in the pan for 4 hours, then refrigerate loosely covered for at least 12 hours to fully set.

8-Final Step: Serve and EnjoyRemove the flan patissier from the refrigerator about 1 hour before serving to reach room temperature. Slice like a cake: the custard will be creamy yet firm, while the pastry remains flaky and crisp. This dessert can also be enjoyed by hand in the traditional French style. Feel free to pair it with savory sides like steak stir fry or shrimp stir fry noodles to create a memorable meal.