Sift the dry ingredients (flour, baking powder, sugar, salt) into a bowl. Add cold butter and mix by cutting it into the flour mixture.

Add cold milk and egg to the mixture and gently mix until it starts to form a dough.

Add yuja marmalade to the dough and mix. Wrap the dough in plastic wrap, flatten it, and refrigerate for at least 30 minutes.

Roll out the dough with a rolling pin, fold it in half, and repeat the folding process three times.

Roll the dough to a thickness of 1.5–2cm and cut shapes using a cookie cutter.

Place the scones on a baking tray, brush the tops with egg wash, and bake in a preheated oven at 180°C for 20–25 minutes.