• Preheat the oven to 180°c / gas 4. Line 2 large baking trays with baking paper and set aside.
• In a large bowl, beat the butter and sugar together until smooth and creamy. Then work in the flour and salt.
• Bring the dough together to form a firm ball and turn out onto a lightly floured surface (see top tip below). Roll the dough out to a thickness of 5mm (¼in) and use a round pastry cutter to cut out circles.
• Use a smaller cutter (or an upturned end of a piping nozzle) to cut the middles out of half of the rounds. Then re-rolling the trimmings until all the dough has been used up.
• Arrange the rounds on the baking trays, allowing space between them for the dough to spread a little. Bake for about 10mins, until golden.
• Cool on a wire rack, then sandwich the biscuits together with the jam.
• Sprinkle with icing sugar before serving.

Top tip

• If your dough looks really crumbly, turn out on a surface and carefully knead together, you will notice it all coming together.