Step 1
Preheat the oven to 220°C/fan oven 200°C/Gas Mark 7. Put a baking sheet into the oven to heat.

Step 2
Sift the flour, baking powder and salt into a large mixing bowl. Add the Trex and rub in with your fingertips until the mixture looks like fine crumbs. Mix in three-quarters of the cheese and all the chives.

Step 3
Add just enough milk to the mixture to make a soft, but not sticky, dough, mixing it in with a knife to bring the dough together. Avoid using your hands, as this warms the mixture.

Step 4
Flour your hands a little, then knead the dough lightly for a few moments. Turn onto a floured surface, then use a lightly floured rolling pin to roll out the dough to about 2.5cm (1in) thick.

Step 5
Use a 5cm (2in) plain cutter to stamp out rounds. Avoid twisting the cutter — just press it straight through the dough to help the scones rise evenly. Gather the trimmings together, re-roll them and cut out more scones.

Step 6
Arrange the scones on the hot baking sheet. Quickly brush the tops with milk and sprinkle with the remaining cheese. Bake for 15-18 minutes, until well-risen and golden brown. Cool for a few moments, then transfer to a cooling rack. Serve warm.