Step 1
Position the oven shelves towards the top of the oven. Preheat the oven to 200°C/fan oven 180°C/Gas Mark 6. Lightly grease two baking trays with a little Trex.
Step 2
Beat the egg and sugar together using a wooden spoon.
Step 3
Put the Trex into a mixing bowl with 150g (6oz) flour and the salt. Beat together with a wooden spoon until smooth and creamy. Gradually beat in the egg and sugar mixture. Add the remaining flour and polenta or semolina and mix together to make a smooth dough.
Step 4
Turn out onto a lightly floured work top and roll out with a floured rolling pin until 5mm (¼ in) thick. Stamp into rounds with a 6cm (2 ½ in) cutter and transfer to the prepared baking trays.
Step 5
Bake for 16-18 minutes until light golden brown. Cool for a few minutes on the trays, then transfer to a wire rack to cool completely.
Step 6
When ready to serve, top the shortcakes with spoonfuls of clotted cream and strawberries, then sprinkle with icing sugar.