Upside-down Rhubarb Brunch Cake has a buttermilk cake base and is topped with tangy rhubarb laced with gooey caramel, which makes this already-moist cake irresistible.

Upside-Down Rhubarb Brunch Cake

This is not your typical upside-down cake from the 80s. This Upside-down Rhubarb Brunch Cake is the real deal.
Course Brunch
Prep Time 25 minutes
Cook Time 40 minutes
Total Time 1 hour 5 minutes
Servings 16
Author breakfast for dinner


For the rhubarb topping:

  • 1/2 cup unsalted butter
  • 1 cup packed brown sugar
  • 2 teaspoons lemon juice
  • 3 cups chopped rhubarb (approx 3-4 stalks)

For the buttermilk cake:

  • 1/2 cup unsalted butter, softened
  • 1/4 cup granulated sugar
  • 1/4 cup packed brown sugar
  • 2 eggs
  • 1 teaspoon vanilla
  • 1 1/3 cups all-purpose flour
  • 1 1/2 teaspoons baking powder
  • 1/2 teaspoon baking soda
  • pinch salt
  • 3/4 cup buttermilk


To make the rhubarb topping:

  1. In a saucepan over medium heat, melt butter, sugar, and lemon juice, stirring until sugar is dissolved. Pour into greased and parchment-lined 8x8" or 9x9" square pan. Sprinkle chopped rhubarb evenly over top.

To make the buttermilk cake:

  1. In a large bowl, cream butter and sugars together until fluffy. Beat in eggs and vanilla.
  2. In a separate large bowl, stir together the flour, baking powder, baking soda, and salt. Add 1/3 dry ingredients to wet ingredients, stirring well. Then add 1/2 buttermilk to mixture; then 1/3 dry; then the rest of the buttermilk, and lastly the remaining 1/3 dry. Make sure to stir well between each addition.
  3. Pour into pan over rhubarb, smoothing to edges of pan. Bake at 350 F for approx 35-40 minutes, until toothpick inserted in centre of cake comes out clean.
  4. Let cool in pan for 10 minutes, then invert onto serving plate, remove parchment paper, and cut into 16 squares.