Beat the butter and sugar until light and creamy.

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract with the final egg.

Add the self-rising flour and salt. Mix just until combined.

Transfer two-thirds of the batter to a separate bowl.

Mix the cocoa powder and milk together until smooth, then stir it into the remaining one-third of the batter.

Spread half of the vanilla batter into the prepared pan.

Add the chocolate batter and spread evenly.

Top with the remaining vanilla batter.

Run a knife through the batter a few times to create the marble effect.

Bake for approximately 60 minutes, or until a skewer inserted into the center comes out clean.

Allow the cake to cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.

Serving tip: Serve with freshly whipped cream and seasonal berries for an easy dessert or afternoon treat.