Custard jam slice

Method

1. Heat the oven to 220°C/200°C fan/gas 7 and line the square tin with baking paper, ensuring there’s plenty of overhang. Take 2 baking trays big enough to fit the puff pastry sheets. Lay a sheet of pastry (still on the baking paper it comes with) on each tray, then top the pastry with another sheet of baking paper and stack another baking tray on top. (Alternatively, if you don’t have 4 baking trays, you can bake the 2 pastry sheets separately.) Bake for 20-25 minutes until golden and crisp, then set aside to cool.
2. Using the base of the square baking tin as a guide, trim the cooled pastry sheets to size to give you 2 x 20cm square sheets. A very sharp serrated knife will work best for this. Put a pastry square in your lined square tin and top with the strawberry jam, spreading it evenly. Set aside while you prepare the custard.
3. Add the milk, cream, butter, vanilla and sugar to a large pan and set over a medium heat. Allow the ingredients to almost come to the boil, then remove from the heat. In a separate bowl, whisk together the cornflour and 125ml water until smooth, then add this to the milk mixture followed by your egg yolks. Put the pan back over a medium heat and bring to the boil, whisking continuously. Once the custard begins to boil it will become very thick but keep whisking vigorously for around 1 minute to cook out the cornflour, then remove from the heat. Immediately pass the custard through a sieve into a jug.
4. Pour the custard over the jam-covered pastry layer, spreading it evenly into the corners, then lay the other square of pastry on top of the custard and press down gently. Put the tin in the fridge to set for a minimum of 5 hours. 5 Once set, gently lift the custard slice from the tin, holding onto the baking paper for support, and place on a chopping board. Dust with icing sugar and cut into portions with a very sharp serrated knife.