For the cake:
1) Preheat the oven to 190C/Gas 5.
1) Butter an 20cm round cake pan, line it with parchment paper, butter the paper, and dust the pan lightly with flour.
2) Whisk the flour with the caster sugar, baking powder, and salt in a medium bowl. Lightly whisk in the butter, egg, milk, and vanilla, just until smooth. Pour the batter into the prepared cake pan and bake until a toothpick inserted in the centre comes out clean, about 25 mins. Cool on a rack for 10 mins, then turn it out of the pan, flip upright, and cool completely on the rack.
For the strawberries and cream:
1) Set aside 350g of the best-looking whole berries for topping the cake. Hull and thinly slice the rest of the berries and toss with the caster sugar. Set aside. Whip the cream with the icing sugar and vanilla to soft peaks. Refrigerate until ready to use.
To assemble the cake:
1) Cut the cake in half horizontally with a serrated knife. Place the bottom layer cut side up on a cake stand or serving plate. Drizzle the juices from the sliced berries over the cut sides of both halves. Fold a couple tablespoons of the whipped cream into the sliced berries and spread over the bottom layer. Top with the other piece of cake, cut side down. Spread the remaining whipped cream on the top of the cake and top the cake with the whole berries.
* Chef's note: Cutting a cake into layers is easy as saw-spin-separate: Begin to saw the cake in half horizontally. Just before you reach the middle of the cake, give it a quarter turn. Continue to saw almost to the centre, then give it another quarter turn and saw again until you reach your original point of entry. Saw completely through the cake's centre and separate the layers.