Preheat oven to 180°C (350°F). Butter a 20cm cake pan.

Whisk or sift flour, baking powder and salt together into a medium bowl.

Place butter and caster sugar in the bowl of an electric mixer fitted with the paddle attachment. Mix on medium-high speed until pale and fluffy, about 3 minutes, and then mix in egg, milk and vanilla.

Reduce speed to low, and mix in the flour mixture in batches. Transfer batter to buttered cake tin. Arrange strawberries on top of batter, cut sides down and as close together as possible. Sprinkle raw sugar over berries.

Bake cake for 10 minutes, and then reduce oven temperature to 160°C (325°F). Bake until cake is golden brown and firm to the touch, about 1 hour. Let cool in cake tin on a wire rack. Dust with icing sugar and cut into wedges. Serve with lightly sweetened whipped cream if desired. Cake can be stored at room temperature, loosely covered, up to 2 days.