Craquelin Beat butter and brown sugar, then add flour very thin. Store it in the fridge. Roll out the craquelin, it must be very thin. Store it in the fridge. Choux pastry Preheat oven to 180°C Place water, sugar, salt and butter in a saucepan over medium heat. Cook until butter melts and mixture just comes to the boil Add all the flour to the butter mixture at once and use a wooden spoon to beat until well combined. Place over low heat and cook, stirring, for 30 seconds to dehydrate the paste. Add eggs 1 by 1 to the flour mixture, beating well with a wooden spoon. Use a pastry bag fitted with a 1.5cm-diameter plain piping nozzle to pipe the éclairs onto the baking tray. Put one piece of craquclin on the éclain. Bake in preheated oven for 25 minutes Custard Put the milk into a large pan and gently bring to just below boiling point. Meanwhile, in a large bowl, whisk the eggs, cornflour and sugar. Gradually pour the hot milk onto the sugar mixture, whisking constantly. Pour the mixture back into the saucepan. Heat gently stearring whit a whip until the custard is thickened, but before any lumps form. Let it cool down and aromatize as wanted.