Rub the cold butter into the flour with your fingers until it looks like coarse crumbs. Add the egg, salt, vinegar and ice-cold water to knead a smooth dough.

Divide the dough into 6 pieces, wrap them and chill for 30 minutes.

Roll each piece thin and bake them one by one in an oven preheated to 180°C until golden.

Cook the milk, sugar, cornstarch and egg yolks over low heat, stirring constantly, until thickened. Stir in the vanilla and let it cool.

Stack the layers with the filling between each one, then crumble the top layer over the finished cake.

Chill the cake for at least 4 hours before slicing and serving.