Method:
1. Preheat the oven to 180 degrees celsius
2. Cut the butter into small cubes and rub into the flour using your fingertips or if possible an electric mixer until it resembles breadcrumbs
3. Add, to begin with, 2 tbsp cold water and stir using a metal knife.
4. Mix to form a firm, smooth dough, using a little more water if necessary
5. Roll out the pastry into a roughly 20cm x 20cm square on a floured surface
6. Cut this into 2 equal rectangles
7. If you are using actual sausages (as opposed to sausage meat) and haven't already, remove their skins
8. Lay the sausage meat in a line down one side of each pastry rectangle and sprinkle with sage
9. Lift the side of the pastry that doesn't have the meat on, and fold over the sausage, sealing the pastry with a little water
10. Press the seal of the pastry down with a fork
11. Cut each roll into 3-4 pieces, depending on how big you want the sausage rolls and snip, using a pair of scissors, a small hole in the top of each
12. Glaze, using a brush, with the beaten egg
13. Transfer the rolls onto a lined baking tray, and bake for 15-20 mins
14. Remove when golden brown and serve warm, or as a cold snack