In the bowl of a stand mixer, combine the flour, sugar, salt, baking powder and soda, pepper, chives and chilli (if using) with the cold cubed butter. Put this in the fridge while weighing out your remaining ingredients.
In another bowl, whisk the egg, sour cream and cream together.
And in another bowl, toss the grated gruyere and green olives together.
Paddle the butter and dries for 2-4 minutes (depending on warmth of your kitchen) until the butter breaks into almond sized pieces.
Add the gruyere and olive mix, and gently paddle together.
Scrape the egg mixture into the bowl and paddle everything until there are no dries remaining. It will help to scrape the mixture off the paddle attachment and ensure those dry bits are collected from the bottom of the dough into the mix. Do you stress about overworking the dough - we want to make sure the dries get incorporated.
Pull the mixture out onto plastic wrap or baking paper, and flatten into a neat rectangle. Wrap up tightly, and rest for a couple of hours, or overnight. We want it to be thoroughly chilled!
Unwrap the scone mix onto a floured bench, and flour the top. Using a rolling pin, roll to about 20-25cm long, then perform a letter fold by cutting the dough into three pieces lengthwise and stacking these on top of each other. Flour the top of the dough and repeat two more times to achieve three letter folds (a total of 27 buttery layers!).
After your last letter fold, roll the dough to roughly 16 x 23cm. Trim each edge slightly, to expose the lovely layers (bundle together the scrap - chef's treat). Cut into 6 neat squares.
You can either bake these right away, or wrap them up to refrigerate or freeze to bake on a later day. When ready to bake, preheat oven to 190℃.
Brush the tops of the scones with egg wash, and sprinkle with flaky salt and a pinch of pepper.
Bake for 26-32 minutes, until the scones are browned all over and feel almost firm when pressed. Allow to cool for 20 minutes before eating.
