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Blueberry Rhubarb Streusel Cake

A moist cake layered with fruit and streusel. It's perfect for celebrations or weekend munching. 

Course Dessert
Cuisine American
Prep Time 30 minutes
Cook Time 1 hour 10 minutes
Total Time 1 hour 40 minutes
Servings 8 servings
Author Laura



  • 1 & 3/4 cups flour
  • 3/4 cup light brown sugar, firmly packed
  • 1 teaspoon cinnamon
  • 1/4 teaspoon ground nutmeg
  • 12 tablespoons unsalted butter, melted (1 1/2 sticks or 3/4 cup)

Cake (Batter and Fruit)

  • 8 ounces rhubarb, cut into pieces about 1/3-inch thick About 2 cups. Be careful to only use the red stalk of the rhubarb - the leaves are poisonous!!
  • 8 ounces blueberries About 2 cups
  • 1 tablespoon fresh lemon juice
  • 3/4 cup granulated (white) sugar, divided
  • 1 1/4 cups flour
  • 1 teaspoon baking powder
  • 1/2 teaspoon fine sea salt
  • 1/3 cup canola (or similar) oil
  • 4 tablespoons unsalted butter, at room temperature
  • 2 large eggs
  • 1 teaspoon vanilla
  • 1/3 cup sour cream
  • 2-3 tablespoons confectioners sugar For sifting over cake just before serving.)


  1. Preheat oven to 350°F. and butter and flour a 9-inch round or square baking pan at least 2 inches deep.


  1. Mix the flour, sugar, cinnamon and nutmeg. Pour the melted butter over the mixture and toss with a rubber spatula just until it forms large crumbs. Set aside. 


  1. Mix the rhubarb pieces, blueberries, lemon juice and ¼ cup sugar in a bowl and set aside.
    Rhubarb and blueberries for the streusel cake - they need to sit in sugar and lemon juice for at least a few minutes.
  2. Whisk together the flour, baking powder, and salt and set aside. 
  3. Put the butter, canola oil, and sugar in a medium bowl. Beat them with an electric mixer or whisk until the mixture becomes light and fluffy (about 2 minutes with an electric mixer.) Add the sour cream and mix until combined. Then add the eggs, one at a time, beating well after each addition, and then vanilla. Sift in the dry ingredients and mix them in until just combined.

  4. Spread the cake batter in the pan, smoothing the top so that it is even and pushing the batter out to the edges of the pan. (The batter is spoonable, not runny.) Using a slotted spoon to drain any juices, spread the fruit over the batter. 
  5. Spread the streusel over the fruit, using your hands to sprinkle it and break up the pieces into irregularly shaped pieces of varying sizes. 
  6. Bake the cake in middle of oven for 1 hour 10 minutes, or until a tester comes out clean. Cool the cake completely in the pan on a wire rack. Once cooled, run a knife around the edges, put a cutting board or large flat plate on the top and flip the cake out of the pan. Then turn it right side up with another plate or a platter. 
    Blueberry Rhubarb Streusel Cake, in pan.
  7. Just before serving (at room temperature), sift confectioners sugar on top.
    Blueberry Rhubarb Streusel Cake | Mother Would Know