Preheat your oven to 200°C (390°F) or 180°C if using a fan-forced setting. Line a baking tray with parchment paper.
In a food processor, combine the flour, baking powder, and salt. Pulse once or twice to mix.
Add the cold butter cubes. Pulse 4 to 5 times until the butter is broken down into small pieces about the size of peas.
Add the shredded cheese and any optional mix-ins. Pulse briefly just to combine.
While pulsing, slowly pour in the milk through the feeder tube. Stop once the dough comes together and there’s no visible dry flour. It should be slightly sticky.
Turn the dough out onto a sheet of parchment paper. Shape it into a round disc about 3cm (1.2 inches) thick.
Brush the top of the dough with a little extra milk. Sprinkle with a small handful of cheese, if you like a cheesy crust. Use a knife to cut the disc into 6 even wedges.
Transfer the wedges to the lined tray, spacing them about 5cm (2 inches) apart.
Bake for 20 minutes, or until the tops are golden and the edges look crisp.
Let the scones cool on the tray for 5 minutes, then serve warm.