Place the flour into a large mixing bowl.
Add the squares of butter to the flour and rub with fingers until it resembles breadcrumbs.
Add the cheese and combine with the salt and pepper. Add the mustard, pepper sauce, chili and 1 egg yolk. Mix together with fingers until a ball forms. Cover with cling film and rest in the fridge for half an hour.
Roll out on a lightly floured surface to 5mm thick.
Using a star shaped cutter, cut out and place onto a non-stick baking sheet. Glaze with an the beaten egg yolks. Place a strip of chilli in the middle of the top of each biscuit.
Bake on the middle shelf of the oven for 12-15 minutes . Remove from the oven and place the cheese stars onto a wire rack to cool.