Mix in the milk with the lemon juice and set aside. Preheat the oven to 220C/gas 7/fan 200C and lightly grease a baking sheet (unless you’re using a non-stick sheet).
Tip the flour into a mixing bowl (mix in the baking powder if you’re using plain flour) with the salt. Add the butter, then rub together with your fingers to make a reasonably fine crumbed mixture. Don’t over rub.
Make a bit of a well in the middle of the flour mixture with a round-bladed knife or a thin spatula, then pour in most of milk mixture, holding a little bit back just in case it’s not needed. Using the knife, gently work the mixture together while adding the vanilla and continue mixing until it forms a soft, almost sticky dough. Work in any loose dry bits of mixture with the rest of the milk. Try not to overwork as you may toughen the dough. Lift the ball of soft dough out of the bowl and put it on to a lightly floured surface. Knead the mixture for about 30 seconds to get rid of the cracks. Pat the dough gently with your hands to a thickness of no less than 2cm and no more than 2.5cm. Dip a 5cm round fluted cutter into a bowl of flour. By doing this you will help stop the dough sticking to the cutter. Cut out the scones by pushing down quickly and firmly on the cutter with the palm of your hand. Don’t twist the cutter. The scone shapes should easily come away from the cutter. Gather the trimmings together and pat and cut out more scones.
Place the scones on the baking sheet. Bake for 10-12 minutes until risen and golden. Cool them on a wire rack. Leave them uncovered if you prefer crisp tops or cover them loosely with a cloth for softer ones.
You can serve the scones with strawberry jam and a generous dollop of clotted cream. I’ve been told that Cornish people put the cream first, then the jam while the Devonians do it the other way round. Or you could do it your own way!