Method
First, make the shortbread. Preheat the oven to 190°C (Gas Mark 5) and lightly grease a baking sheet or tray. Separate the egg, reserving the white for later use (a great excuse to whip up some meringues!), and add the yolk to the bowl of a food processor, together with the butter. Sieve in the flour and icing sugar, then blitz until the mixture comes together to form a smooth dough. Sieve a little flour over your work surface and rolling pin, then dust your hands lightly with flour and lift the dough on to the floured surface. Roll it out to about 0.5cm thick, then use a round pastry cutter to cut out biscuit shapes (whatever size you choose, bear in mind that you’ll need a pair of biscuits to make each finished shortbread). Place the rounds on the prepared baking sheet and put it into the hot oven for about 8 minutes, or until the shortbread becomes a light golden brown. Remove the tray from the oven and place on a wire rack to cool. While the biscuits are cooling, wash and hull the strawberries, then chop them into small, evenly-sized pieces (you can leave a couple whole to decorate the plate, if you like). When the biscuits have cooled, put the cream into a large mixing bowl, then add the vanilla extract and sieve in the icing sugar. Beat with an electric whisk until soft peaks form when you lift the whisk up out of the cream. Gently fold the strawberry pieces into the cream, then use the cream mixture to sandwich the biscuits together in pairs. Place on a serving plate and sieve over a little icing sugar to dust, adding the whole strawberries and mint sprigs for decoration (if using), then serve.