This rhubarb streusel cake with warm vanilla sauce is unreal in it’s deliciousness. Tart rhubarb folded into a moist buttermilk cake. Yum!

This cake. Oh, this cake. It is so unreal in it’s deliciousness that I had to post about it immediately.

I love me some rhubarb but have only ever enjoyed the pie and crisp variety of rhubarb desserts. Until this cake, that is.

Piece of rhubarb cake with a fork taking a bite out and sauce drizzled over the top.

Leisel, a sweet reader, sent it my way, telling me it turned her rhubarb-hater of a husband into a rhubarb-lover.

Since I was already a lover of rhubarb, it completely sealed my fate to adore rhubarb forevermore.

Tart rhubarb is folded into a deliciously moist and sweet buttermilk cake and topped with a buttery, crunchy streusel.

Baked to golden perfection, the cake retains it’s moistness and the rhubarb softens to perfect puckery tenderness.

Smothered in the creamy sweetness of the warm vanilla sauce and this unbelievable cake becomes absolutely irresistible.

Piece of rhubarb cake with streusel and sauce on top.

Rhubarb Streusel Cake with Warm Vanilla Sauce

4.56 stars (50 ratings)



  • 2 tablespoons (28 g) butter, softened
  • 1 cup (212 g) sugar
  • 1 large egg
  • 2 cups (284 g) all-purpose flour
  • 1 teaspoon baking powder
  • ½ teaspoon baking soda
  • ½ teaspoon salt
  • 1 cup buttermilk (see note)
  • 2 cups chopped fresh or frozen rhubarb

Streusel Topping:

  • ½ cup (71 g) all-purpose flour
  • ½ cup (106 g) sugar
  • 4 tablespoons (57 g) butter, melted

Vanilla Sauce:

  • ½ cup (113 g) butter
  • ¾ cup (159 g) sugar
  • ½ cup evaporated milk
  • 1 teaspoon vanilla extract


  • Preheat the oven to 350 degrees. Lightly grease a 9-inch square baking dish and set aside.
  • In a large mixing bowl, cream together the butter and sugar for the cake. Beat in the egg. In a smaller bowl, whisk together the flour, baking powder, baking soda and salt. Add the dry ingredients to the creamed butter/sugar mixture alternately with the buttermilk, beating just until moistened. Fold in the chopped rhubarb. Pour the batter into the prepared pan and smooth the batter to the edges.
  • In a medium bowl, combine the streusel topping ingredients, mixing them together until the mixture is coarse and combined. Sprinkle the streusel evenly over the batter. Bake for 40-45 minutes or until a toothpick comes out clean and the top of the cake is lightly browned. Cool on a wire rack.
  • For the sauce, melt butter in a medium saucepan. Add the sugar and milk. Bring to a boil; cook and stir for 2-3 minutes or until slightly thickened (it will thicken more as it cools slightly). Remove from the heat; stir in the vanilla. Serve warm with the cake.


Buttermilk: here is a guide for making your own buttermilk. 
Cake/Cupcakes: I doubled this cake – it was too much batter for a 9X13-inch pan so I made 9 cupcakes in liners (filling them about 1/2 to 2/3 full) and a 9X13-inch cake. The cupcakes baked for about 23-25 minutes, the cake for about 40 minutes.
Serving: 1 Serving, Calories: 528kcal, Carbohydrates: 81g, Protein: 7g, Fat: 21g, Saturated Fat: 13g, Cholesterol: 75mg, Sodium: 447mg, Fiber: 1g, Sugar: 53g

Recipe Source: adapted slightly from a reader, Leisel, who got it by way of