01 -
Preheat the oven to 175°C. Grease and flour a 23cm round cake pan to ensure easy removal of the baked cake.
02 -
Chop the rhubarb into small pieces and rinse thoroughly under cold water. Drain and set aside.
03 -
In a large mixing bowl, whisk together granulated sugar, eggs, vegetable oil, and vanilla extract until the mixture is smooth and aerated. Stir in the milk.
04 -
Gradually fold in the all-purpose flour, baking powder, baking soda, and salt into the wet mixture, mixing until just combined.
05 -
In a small saucepan, whisk together 120ml milk, custard powder, and a portion of sugar over medium heat. Cook, stirring constantly, until the mixture thickens into a smooth custard. Remove from heat.
06 -
Spread the cake batter evenly in the prepared pan. Distribute the chopped rhubarb over the surface, then gently pour the custard over the batter. Swirl the layers together using a spatula for a marbled effect.
07 -
Place the pan in the center of the oven and bake for 35–40 minutes, or until a skewer inserted in the centre comes out clean and the top is golden.
08 -
Remove the cake from the oven and allow it to cool in the pan for 10 minutes before transferring to a wire rack. Serve warm or at room temperature.