Rhubarb Custard Cake

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4.6 from 11 reviews

A stunning Rhubarb Custard Cake with a thick custard layer baked in the centre of the cake. Delight your family and friends with this beautiful rhubarb cake.


For the custard (see Kitchen Notes)

For the rhubarb cake


To make the custard (see Kitchen Notes)

  1. Mix together the custard powder and caster sugar in a small saucepan.
  2. Whisk in the milk.
  3. Bring the mixture to a boil, stirring frequently.
  4. The mixture will start to thicken very quickly and, when it does, take the pan off the heat.
  5. Whisk in the butter and vanilla extract.
  6. Place some clingfilm directly onto the surface of the custard to prevent a skin from forming and leave to cool.

To make the rhubarb cake

  1. Preheat the oven to 180°C (350°F) (without fan).
  2. Cream the butter and sugar until it is light and fluffy.
  3. Beat in one egg at a time, together with a tablespoon of the flour to help it all come together.
  4. Add the remaining flour, baking powder and custard powder, and mix well. The batter will be quite thick because there is no liquid, but it should still be spreadable.
  5. Line the bottom of a 20 cm (8 inch) springform cake pan with baking paper and grease the sides of the pan.
  6. Use a small spatula to spread half of the batter in the cake pan. Remember that it is a thick batter so you will have to make sure that it covers all of the surface.
  7. Spread the now cooled and thickened custard over the first layer of the cake batter.
  8. Dollop spoonfuls of the remaining cake batter over the custard and carefully spread the cake batter to completely cover the custard. Again, a small spatula works well here.
  9. Chop the rhubarb into 10 cm lengths and slice them lengthwise, about 1 cm thick.
  10. Arrange the rhubarb as in the photo, trimming them where necessary.
  11. Brush the top of the cake with melted butter and sprinkle generously with granulated sugar.
  12. Bake for about 1 hour to 1.5 hours, or until a skewer inserted in the top cake layer comes out clean.
  13. Remove the cake from the pan and cool on a wire rack.

Kitchen Notes

Forced rhubarb, i.e. the bright pink rhubarb, works really well in this recipe because it keeps its colour upon baking. However, the regular type of rhubarb (i.e. the red and green variety) would also be great in this recipe.

As a slight variation to the cake above, and as an attempt to squeeze more rhubarb into the cake, slice the rhubarb into 1 cm pieces and arranged them randomly on top of the cake before sprinkling generously with granulated sugar.

If custard powder is not available where you live, I would suggest replacing the custard powder in the cake batter with an equal quantity of cornflour (cornstarch) plus 1-2 teaspoons of vanilla extract.

If you cannot find custard powder, making a custard from scratch is very easy to do. Heat 300 ml (1 1/4 cup) double cream (heavy whipping cream) in a small saucepan with 1 split vanilla bean. In a medium bowl, whisk together 3 egg yolks, 3 teaspoons of cornflour (cornstarch) and 2 tablespoons of caster sugar (superfine sugar). When the cream has nearly come to a boil, remove the vanilla bean. Slowly pour the cream into the egg mixture, whisking constantly as you do. Pour the mixture back into the saucepan and continue whisking over medium heat until the custard has thickened substantially. The custard needs to be thick such that it is not runny and can hold its shape. Leave the custard aside to cool while you proceed with the rest of the recipe.

Recipe adapted from The Cake Stall by the Australian Women’s Weekly.

All recipes on this website state temperatures for a regular oven (i.e. a conventional oven without fan). If you have a convection oven with a fan, please consult the manufacturer’s handbook on how to adjust the temperature and baking time accordingly.

To convert from cups to grams, and vice-versa, please see this handy Conversion Chart for Basic Ingredients.