Rhubarb Upside Down Cake

The nutty hazelnut sponge in this simple Rhubarb Upside Down Cake is topped with sweet, tangy rhubarb. This dessert is stunningly sweet and flavorful when served with a blood orange syrup.

Ingredients

Rhubarb

15 g unsalted butter, room temperature
30 g granulated sugar
400 g forced rhubarb, trimmed (approx. 4-5 stalks)

Hazelnut batter

180 g unsalted butter , room temperature
100 g granulated sugar
1 blood orange, zest
1 tsp vanilla extract
3 large eggs , room temperature
120 g plain flour (all-purpose)
100 g hazelnut meal (ground hazelnuts)
1 tsp baking powder
¼ tsp fine salt
60 ml milk at , room temperature

Blood orange syrup

180 ml blood orange juice, freshly squeezed approx, 3 to 4 oranges
50 g granulated sugar

Pouring orange syrup over rhubarb cake slice.

Instructions

Make the cake

Make sure the cake pan is ready. Preheat the oven to 180 degrees Celsius (350 degrees Fahrenheit). Grease and line the bottom and sides of a 22cm (8-inch) round cake pan or springform pan with parchment paper. Dollop butter evenly across the bottom of the lined pan. Sugar is sprinkled on top.
Prepare the rhubarb by chopping it up into small pieces. Trim rhubarb stalks to fit side by side in the pan, covering the bottom. Keep any leftover rhubarb offcuts and chop them into 1cm (0.5inch) pieces. Remove from the equation.
Butter, sugar, and orange zest are combined in a mixing bowl. 5 minutes on high, beat the butter, sugar, and blood orange zest in the bowl of a stand mixer fitted with the paddle attachment until pale and fluffy.
Toss in the eggs. Add the vanilla essence, then beat in the eggs one at a time on medium to high speed until barely incorporated. After each addition, scrape down the edges of the basin.
Combine the dry ingredients in a mixing bowl. In a separate medium bowl, whisk together the dry ingredients: flour, powdered hazelnuts, baking powder, and salt.
Combine the remaining ingredients in a large mixing bowl. Mix in half of the flour on low speed until barely mixed, then add the milk and chopped rhubarb and mix again. Finally, whisk in the remaining flour mixture until just a few streaks of flour remain.
Bake after spooning into pan. With a spatula, spread the cake batter evenly over the rhubarb stalks in the bottom of the prepared pan. Bake for 50-60 minutes, or until a toothpick inserted in the middle comes out clean. Allow 10 minutes for the cake to rest. Invert the cake onto a platter by gently running a thin-bladed knife over the edge of the pan. Remove the parchment and allow it cool fully before using.

Blood orange syrup

Make the orange syrup in a saucepan. Make the blood orange syrup while the cake is baking. In a saucepan, combine the blood orange juice and sugar, and cook over medium heat, stirring constantly until the sugar dissolves. Increase the heat to medium-high and continue to boil for 10 to 15 minutes, or until the syrup thickens. Any froth that forms should be skimmed away. Allow to cool after removing from the heat.

To serve

Drizzle half of the blood orange syrup over the cake before serving. Slice and serve with a dollop of cream and a little extra syrup.

All recipes are developed and tested in Metric grams. I strongly recommend that you bake using digital scales for a more accurate result. I have provided a conversion to US customary in the recipe but please note that I haven’t tested using this method.

Notes

To preserve, keep the Rhubarb Upside Down Cake refrigerated for up to 4 days. Wrap tightly with plastic wrap and keep in the refrigerator in an airtight container.
Allow the cake to cool fully before freezing. Then wrap the cake in plastic wrap and cover the fruit with parchment paper. Refrigerate for up to 3 months in an airtight container. Before serving, thaw overnight in the refrigerator and bring to room temperature.
TIP 1: Use the most vibrant, colorful forced rhubarb you can find. The color diminishes when cooked, thus the brighter the raw rhubarb, the better the color after baking.
TIP 2: Check that the butter is at room temperature before using it. While butter is creamed, it aerates and retains air, which gives the lift needed for a light sponge when baking. Cold butter will not provide the desired aeration.
TIP 3: Scrape the bottom and sides of the mixing bowl on a regular basis. This is done after each ingredient has been added to the mixing bowl. It simply ensures that all of the components are evenly distributed throughout the batter.
TIP 4: Release the oils to get the most out of your zest. Before using the butter, massage it into the sugar. Just don’t wait to mix the zest in with the flour; else, you’ll be missing out on a great opportunity to add extra flavor.
TIP 5: Push the rhubarb together as closely as possible when putting it on the bottom of the pan. This prevents the cake batter from soaking through and ensures a nicer finish when the cake is upturned at the end.