Sift the flour and baking powder into a mixing bowl or a food processor. Add the butter and rub in with your fingertips or process until the mixture resembles fine breadcrumbs. Stir in the sugar. Gradually add the egg and milk and continue mixing until the mixture just comes together to form a dough.
Roll out the dough on a lightly floured surface until 1 cm (½ inch) thick. Stamp out 8 x 7 cm (3 inch) circles using a plain round biscuit cutter. Transfer to a large, lightly oiled baking sheet and brush each round with a little melted butter.
Bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 10–15 minutes until risen and golden. Remove from the oven and transfer to a wire rack to cool. While they are still warm, carefully slice each cake in half horizontally and return to the wire rack to cool completely.
Make the elderflower cream. Put the cream and elderflower syrup in a mixing bowl and whip until thickened. Spread the cream over the base of each cake, top with sliced strawberries and the cake lids. Serve dusted with icing sugar.