Preheat oven to 180°C (160°C fan) and line a 2lb loaf tin with parchment.
Cream butter and sugar together until pale and fluffy. Add eggs one at a time, mixing well after each addition. Stir in the vanilla. Sieve flour, baking powder and salt, then fold into the mixture to form a soft batter.
Spoon into the tin and bake for 25–30 minutes until golden and a skewer comes out clean.
Cool in the tin for 5 minutes, then transfer to a wire rack and cool completely.
To prepare the loaf: Re-line the loaf tin with a long strip of parchment with overhang for easy removal. Slice the cooled sponge in half lengthwise. Place one sponge half into the base of the tin and spread with half the strawberry jam. Arrange halved strawberries around the inside edge of the tin, cut side facing out.
To make the filling: Whip 200ml cream with the icing sugar and vanilla until thick. Fold through chopped strawberries. Spoon the mixture over the jam-covered sponge.
To assemble: Spread the remaining jam on the cut side of the second sponge. Place it jam-side down on top of the cream, pressing gently. Cover and chill for at least 4 hours (preferably overnight).
Serving Suggestions
Lift the cake from the tin using the parchment overhang. Carefully peel away the parchment to reveal the strawberry-lined sides. Whip 150ml cream, pipe a line down the centre and decorate with fresh strawberries.