To begin, sift the flour into a large bowl and add cold butter. Rub the butter into the flour with your fingertips until the mixture resembles coarse crumbs. In a separate bowl, whisk the egg, vinegar, water, and salt, then combine with the flour mixture. Knead just until a dough forms. Do not overwork. Cover and chill for 1 hour. Transition to preparing the cream.

In a saucepan, heat milk over medium heat until warm but not boiling. In a bowl, whisk egg yolks with sugar until pale. Add flour and cornflour, whisking until smooth. Slowly pour the warm milk into the egg mixture, stirring constantly to prevent curdling. Move to the stove for cooking.

Return the mixture to the saucepan and cook over medium to low heat, stirring continuously until it thickens to a pudding like consistency. Remove from heat and stir in vanilla extract and softened butter. Let cool completely before using. Chill if preparing in advance.

Divide the chilled dough into 6 equal parts. Roll each piece into a thin circle (around 20 cm). Prick each layer with a fork to prevent puffing. Proceed to baking.

Preheat the oven to 200°C (fan 180°C). Bake each rolled dough circle on a parchment lined baking sheet for 10–12 minutes until golden and crisp. Repeat for all layers. Allow to cool on a rack. Reserve one layer for crumbs.

Take one cooled pastry layer and crumble it finely. This will be used to coat the cake’s surface later. Set aside in an airtight container to keep dry.

Place one pastry layer on a serving plate. Spread a generous layer of custard cream evenly on top. Repeat with the remaining layers, finishing with cream on the top and sides. Work quickly to prevent the cream from drying.

Gently press the reserved crushed pastry onto the top and sides of the cake. This adds a signature rustic finish and absorbs any extra moisture from the cream.

Cover the assembled cake and refrigerate for at least 8 hours or overnight. This allows the layers to soften slightly and meld with the custard, enhancing both flavour and texture.

Slice and serve chilled. Dust with icing sugar or garnish with fresh berries if desired. Presentation tip: Use a hot knife for clean slices and wipe between cuts for a refined look.