Line a baking tray with parchment paper or a reusable liner.
Put 225 g (2 cups) self-raising flour and 1 tsp baking powder in a bowl.
Cut 100 g (2oz) chilled butter into to cubes and add it to the flour. Use a blunt knife to cut it into the flour. Then rub the butter into the flour with your fingertips, until it looks like breadcrumbs.
Add 50 g (⅓ cup) caster (superfine) sugar to the crumb mix and stir it in.
Then crack 1 egg into a jug or other measure and beat with a fork. Add up to 100 ml (½ cup0 milk or cream until the measure reaches 150ml.
Gradually add this mixture to the flour bringing the liquid and flour together into a soft dough, you may need a little less or a little more depending on your flour.
Pat the dough out to about 1.25cm (½ inch), cover with plastic wrap and put into the fridge for 20 mintues.
Cut into rounds with an 85 mm (3 ¼ in) cookie cutter and place on the baking tray.
Brush the tops of the shortcakes with milk, or some of the milk/egg mix if you have any left.
Sprinkle with demerara or granulated sugar.
Bake for about 10 minutes until the scones are pale golden brown.
Remove from the baking sheet and cool on a wire rack.
To assemble
Take one cooled shortcake per person and split them in half.
Spread 1 tsp strawberry jam on the base of each scones and place on a serving plate.
Whip the double (heavy) cream to soft peaks. Then top the shortcake with a spoonful of whipped cream. If you are using clotted cream then simply add a spoonful on top of the jam. Keep back 4 teaspoons of cream.
Set aside 4 of the best strawberries (preferably quite small) for the top of the shortcakes.
Hull and slice the remaining 8 strawberries and sprinkle with a teaspoon of caster sugar and ¼ tsp lemon juice
Divide the strawberry slices between the four scones and place the second shortcake half on top.
Add a teaspoon of cream and top with a small whole strawberry. Dust with icing (confectioners) sugar if liked.
Notes
If you don't have time to make scones, you can always buy some good quality scones and layer them up with jam, cream and strawberries.