Place the milk in a saucepan and heat until almost boiling.
Whisk the sugar, egg yolks cornflour and vanilla paste together in a large bowl. Gradually whisk in the hot milk until well combined. Return to the pan. Cook gently, stirring, until the mixture thickens.
Remove from the heat and return to the bowl. Add the butter and stir until melted Cover with a sheet of baking parchment and leave to cool, then chill until required.
To make the fruit compote
Place the rhubarb and sugar in a small pan and cook gently stirring occasionally until the rhubarb is tender. allow to cool, then chill until required.
To make the pastries
Unwrap the pastry and place on a lightly floured worktop. Using the 9cm cutter, cut out 9 discs and place on lined baking sheet. Chill while you make the choux pastry.
Preheat the oven to 220°C(200°C fan)425°F/Gas mark 7. Place the butter in a saucepan with 150ml (¼ pint). Heat gently to melt the butter, then bring to the boil.
Remove from the heat and immediately add the flour. Beat with a wooden spoon to form a smooth ball of dough that leaves the sides of the pan.
Allow to cool slightly, then beat the egg into the hot dough, a little at a time, until the dough is stiff and glossy.
Spoon the mixture into a piping bag fitted with a 1cm (½ in) plain nozzle.
Pipe a circle of choux pastry leaving a ½cm (¼ in) border on each pastry disc.
Bake for 20–25 minutes, until puffed, crisp and golden. swap the trays around for the last 5 minutes of cooking. Remove from the oven and transfer to a wire rack to cool completely.
Spoon the rhubarb compote into the pastry shells. Then spoon or pipe the crème pâtissière over the top. Sprinkle half a teaspoon of demerara sugar over the top and, using a blowtorch, brûlée the sugar.
Best eaten as soon as possible after assembling.Nutrition information is calculated using an online nutrition database - is approximate and is meant as a guideline only.