Lavender Rhubarb Upside-Down Cake Recipe – Jojotastic | PNW Lifestyle Blogger (2024)

Preheat oven to 350 F. Trim the rhubarb to the length of the cake tin, so that you have enough to cover the entire surface.

In a food processor, add the sugar and lavender buds and pulse until lavender is broken up into small bits and incorporated into the sugar. You can also totally do this in a mortar and pestle. Transfer to a large, shallow dish and mix in the vanilla bean paste. Add the rhubarb stalks and toss in the sugar, coating it thoroughly. Allow it to hang out in the sugar while you prepare the batter. The rhubarb will start to soften in the sugar and release some of its juices. This is good.

Butter a 9 inch round cake pan that’s at least 2 inches tall. You can also use a springform pan like I did but just be sure to wrap the bottom in foil well to catch any rhubarb juices. Butter the bottom and sides and cut a piece of parchment paper to fit the bottom and place it inside and butter the parchment as well. With your fingers, spread the 4 tablespoons of butter all over the bottom of the pan in an even layer. This will become part of the topping once we add the rhubarb and sugar in a bit.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt and set aside.

In the bowl of a stand mixer fitted with the paddle attachment, combine the butter and sugar and beat on medium-high speed for about two minutes, until light and fluffy. Add the eggs, one at a time, mixing thoroughly after each addition. Add in the vanilla bean paste. With the mixer on medium-low, add in about a third of the flour mixture, allowing to mix until mostly incorporated, followed by half the buttermilk mixture, and repeat with another third of the flour mixture, repeating until both mixtures are gone. You should start and end with the dry ingredients. Mix until batter is smooth and everything is fully incorporated.

Arrange the rhubarb in the bottom in a single layer. You can get intricate and create a pattern or you can simply lay the rhubarb across in strips. I went for a spoke pattern by layering the strips up in a circular pattern until the whole bottom was covered. But this is your cake so feel free to do whatever design you’d like! The only thing I’d advise is to be sure to keep the rhubarb pieces as tightly together as you can since it will shrink in the oven slightly. Sprinkle over the remaining sugar mixture and any rhubarb juices evenly over the rhubarb.

Pour the batter over the rhubarb and smooth out with an offset spatula or back of a spoon. Bake for 35-40 minutes, until a toothpick inserted comes out clean. Allow to cool for just a couple minutes then flip cake over by placing a plate or serving platter slightly larger than the cake pan on top and using potholders, quickly and swiftly flip the cake over onto the plate and gently lift the cake pan up, revealing your design. The cake pan should come off fairly cleanly since we lined the bottom in parchment. Peel off the parchment. Allow to cool then serve with fresh whipped cream or ice cream.