1. Preheat the oven to 220°C. Sift the flour and baking powder into a bowl. Rub in the butter with your fingertips until the mixture resembles fine breadcrumbs. Stir in the caster sugar and make a well in the centre.
2. Mix together the egg, milk and vanilla extract, and pour into the dry ingredients. Gradually stir the dry ingredients into the liquid, then bring the mixture together with your hand to form a soft dough. Gently pat the dough into a smooth ball and turn it out onto a lightly floured surface.
3. Roll out the dough into a 19 cm round. Transfer it to a greased baking tray and bake for 10–15 minutes, or until well risen, firm and browned on top. Slide the shortcake onto a wire rack and leave to cool.
4. Using a large serrated knife, slice the shortcake horizontally in half. With a large fish slice, lift the top layer off and place it on a board. Cut into 8 equal wedges, leaving them in place. (If you like, for an attractive finish, trim a fraction off each cut so that the wedges are slightly smaller.) Place the bottom layer on a serving plate.
5. For the filling, reserve 8 whole strawberries, then hull and thickly slice the remainder. Whip the cream until it forms soft peaks. Stir the yogurt until smooth, then gently fold it into the cream.
6. Spread the cream mixture thickly over the bottom shortcake layer and cover with the sliced strawberries, pressing them into the cream.
7. Sift the icing sugar over the top of the shortcake wedges. Carefully put the wedges into place on top of the shortcake. Slice each reserved strawberry lengthwise, leaving the slices attached at the stalk end, then open the slices slightly to fan them out. Place a strawberry fan on each wedge of shortcake. Eat within a few hours.