When rhubarb is in season, there are innumerable ways to use it. But this easy-to-make rhubarb buttermilk cake may be one of the best ways! With bite-sized pieces of rhubarb and a sweet cinnamon sugar topping, the batter comes together quickly with little fuss. Once baked, the cake puffs up slightly to form the perfect spring dessert.
Sprinkle 1 tsp of salt over the chopped rhubarb and mix to combine. Pour the rhubarb into a colander fitted over a bowl to catch the liquid. Allow the rhubarb to macerate until about ¼ to ⅓ cup of liquid accumulates, 45-60 minutes. Once the rhubarb has macerated, discard the liquid and make the cake.
Butter two 8 ½ x 4 ½ loaf pans and set them aside. Preheat the oven to 350°F.
In a large bowl, combine the butter, white granulated sugar, and brown sugar. Using a whisk or a mixer, beat the mixture until light and fluffy, 2-3 minutes. Add one egg and mix to incorporate. Repeat with the second egg and vanilla extract.
To the wet ingredients, add the flour, baking soda, baking powder, and ½ tsp salt. Whisk to combine and slowly add the buttermilk while folding. Once the buttermilk is added, add the prepared rhubarb and fold until it is just mixed in. Pour the batter into the two prepared loaf pans and spread the top of each one to an even layer.
In a separate bowl, mix together the white granulated sugar and cinnamon and sprinkle the mixture evenly over the two cakes.
Bake at 350°F for 45-55 minutes until golden brown and a skewer inserted into the middle comes out clean. Once baked, remove the cakes from the oven and allow them to cool for 20 minutes before slicing.
If your rhubarb stalks have varying widths, slice those stalks that are extra wide in half. This will ensure the rhubarb bakes evenly in the cake without retaining its crunchy texture.
After macerating the rhubarb for up to 1 hour, if not much liquid has pooled on the plate, you can pick up a handful of the rhubarb and squeeze it. This will release additional liquid that will drip through the colander.
Having the butter at room temperature will allow the sugars and butter to cream much easier and allow this to be made by hand. Simply set the butter on the counter for 1 to 2 hours before beginning to prepare the cake to allow it to soften.