1. Mix together plain flour, semolina and sugar.
2. Rub in butter until the mixture binds together.
3. Divide the mixture in half and shape into a round, 1cm thick.
4. Place on a baking tray and prick with a fork.
5. Bake at 160c/gas mark 4 for 30 - 40 mins. Cut into 8 wedges while still warm.