I found my basic scone recipe somewhere online and it is the best of all time. I even have it memorized!
Heat oven to 450 F.
1.5 cups flour
1.5 tsp baking powder
2.5 tbsp sugar
.5 tsp salt
Cut in/finger in/pulse in 1/4 cup butter (half a stick) and then mix in (a fork works fine) 2/3 cup milk or buttermilk. I like this recipe because ordinary milk works just fine and I rarely have buttermilk on hand.
With this base you can add anything you please. I'd been wanting to try lemon and blueberry together and had both in the fridge finally, so I zested 1 lemon and tossed a handful of blueberries into the batter before cutting them out.
I prefer to make proper round scones, patting it down to about 1.5 inches and using a (gulp) glass to cut them out. A regular biscuit cutter would be optimal. But I make do with what I can.
Brush the scones with a mixture of a bit of milk and an egg yolk. Or don't. That just makes them brown nicely, but if you don't mind a paler scone, you can pop them straight in the oven. I actually don't prep the baking tray--I have used spay-on butter and such before but find it makes things burn more. Parchment/baking paper would be best though. Like I said, I make do.
Bake for 8-10 minutes or until golden brown (if you have coated them).
Enjoy and experiment!