In a large bowl mix flour with the salt, baking powder, and sugar. Add the butter, then rub it in with your fingers until the mixture looks like fine crumbs.
Heat up the milk on the stove until warm, but not hot. Add the vanilla and lemon juice, then set aside for a moment. Line a baking sheet with a silicone baking mat and put it in the oven.
Add the milk mixture to the dry mixture and combine them quickly with a fork.
Scatter some flour on the work surface and tip the dough out. Dredge the dough and your hands with a little more flour, then fold the dough over 2-3 times until it’s a little smoother. Don't overwork the dough. Pat into a round about 1.5-inch (4cm) high.
Use a 2 1/2 inch round cookie cutter and plunge into the dough, repeat until all the dough is used. You should get 8 scones.
Brush the tops with egg wash, then carefully place onto the hot baking tray.
Bake for 10-15 mins until risen and golden on the top. Eat just warm or cold on the day of baking generously topped with jam and clotted cream.
If freezing, freeze once cool. Defrost, then put in a low oven for a few minutes until warm.