Preheat the oven to 180°C (gas mark 4, 350°F) and line a baking tray with parchment paper.
In a large mixing bowl, add self-raising flour, sugar, salt and baking powder and mix together.
Then add cubes of butter to the mixing bowl, using the ‘rub-in-method’ use your fingertips to combine the butter and flour together until combined and resembles crumbs. Or you can use a food processor.
Make a well in the middle and add milk and vanilla to the mixing bowl. Gently mix together until a dough has formed, you may need to bring the dough together with your hands.
Dust your worktable with flour and add a little to the rolling pin. Gently roll the dough out with your rolling pin, you only need to flatten the dough a little. The thickness of an inch or 3 cm is ideal.
With a large cookie cutter, cut-out circles and place on a lined baking tray. Try not to twist the cutter when pressing down, you’ll want a clean cut by sharply pressing down.
With a basting brush (pastry brush) gently coat the scones with an egg wash by whisking an egg. Then bake in the oven for 12 to 15 minutes.