Preheat your oven to 160°C (fan-assisted convection). Grease and line an 18cm or 20cm cake tin with baking paper.

Prepare the crumble by mixing the melted butter with 100g of the cake mix until a course crumbles forms. Set aside for later.

For the cake, whisk the egg until foamy, then whisk in the melted butter and yoghurt until well combined. Add the remaining 200g of cake mix and whisk to form a smooth batter.

Spread the cake batter in the prepared tin, then carefully spread the berry jam on top as evenly as possible. Lastly, sprinkle over the crumble mixture.

Bake the cake for 25-30 minutes or until the crumble topping is crunchy and a skewer inserted into the centre of the cake comes out clean.

Allow to cool completely before removing from the tin. Slice and serve with dollops of whipped cream.

Tip: If your jam is too firm to spread over the cake batter, soften it in the microwave in 10 second increments, stirring well with a spoon in between bursts.