1 carrot, peeled, finely chopped
1 celery stalk, trimmed, finely chopped
1 onion, peeled, chopped
brown sauce
225/8oz plain flour, plus extra for dusting
1 tbsp Worcestershire sauce
pinch salt
1 tbsp tomato purée
1-2 tbsp vegetable oil
75g/2¾oz mature Lancashire cheese, or similar mature crumbly cheese, grated
75g/2¾oz chilled butter, cut into cubes, plus extra for greasing
1 free-range egg, beaten
1 free-range egg yolk
250g/9oz beef mince
splash bitter ale