Prep your ingredients and line a baking tray with parchment paper
Add the butter and flour into a mixing bowl. Rub together with your fingers (or use a pastry cutter) until the mixture looks like fine bread crumbs.
Stir in the salt, pepper, chives, and most of the cheese, leaving about 2 tbsp to sprinkle on top of the scones before you bake them.
In a separate bowl or measuring cup, mix the egg with ¾ of the milk and (optional) mustard. Pour into the flour mixture, mixing a with a wooden spoon to roughly combine the wet and dry ingredients. Add leftover milk a bit at a time until everything comes together to form a dough.
Divide the dough into two even pieces and very gently roll the pieces into large balls on a lightly floured surface. Flatten each one lightly, folding them over like a book, and then lightly flattening out again.
Cut each into four wedges or use a cookie cutter to make as many scones as the dough allows (usually about 8).
Place scones on baking tray and sprinkle the remaining grated cheese onto the scones. Place the tray in the fridge for 45 minutes or the freezer for 15-30 minutes to set the butter.
Pre-heat the oven to 180 C / 160 C fan / 350 F / Gas 4.
Place the scone tray into the preheated oven for 10-15 minutes or until they rise, looking golden. Let them cool for a few minutes and then tuck in!
