Preheat the oven to 180°C, grease a rectangular baking pan, and line the base with parchment paper so the finished cake releases cleanly after baking.
In a large bowl, beat softened butter with sugar until pale and fluffy, then add eggs gradually, mixing well after each addition until fully incorporated.
Combine flour with baking powder and salt, then add the dry mixture alternately with milk, stirring gently until a smooth and evenly blended batter forms.
Stir in vanilla extract, pour the batter into the prepared pan, level the surface, and bake until golden and a skewer emerges completely clean inside.
While the cake cools, heat sugar in a saucepan until amber, then carefully add warm cream and butter, stirring until a smooth caramel sauce develops.
Allow the caramel to cool slightly, then spread or drizzle it generously over the cooled cake, making sure the entire top is evenly coated smoothly.
Chill briefly until the caramel sets, then cut the cake into neat rectangles and serve with fresh berries, whipped cream, or extra caramel if desired.
