Method
1. Pre-heat oven - 200°C
2. Grease a clean baking sheet
3. Add egg and buttermilk to a clean small bowl
4. Whisk together and set aside
5. Add all purpose flour, baking powder, dry mustard, salt, black pepper and cayenne pepper to a clean large mixing bowl
6. Whisk briefly
7. Rub in unsalted butter until coarse crumbs form
8. Add buttermilk-egg mixture
9. Add cheddar cheese and fresh sage
10. Mix briefly until dough forms
11. Turn out on lightly-floured surface
12. Flatten by hand until 1 cm thick
13. Cut out 3 inch rounds with a cookie cutter
14. Place rounds on baking sheet
15. Add egg to a clean small bowl
16. Mix in buttermilk to the egg
17. Brush scones with egg-buttermilk mixture
18. Sprinkle with cheddar cheese
19. Bake - 13 min, 200°C
20. Serve