Rhubarb Cake With Coconut Pecan Topping


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Rhubarb Cake With Coconut Pecan Topping Recipe

close up bite of cake

Here is a rhubarb cake with coconut pecan topping for that person with a huge sweet tooth! The cake is dense, moist, and rich. Spread the boiled topping made of brown sugar, butter, coconut, and chopped pecans over the still-warm cake, so all that buttery richness soaks in.

I was immediately intrigued when I saw a picture of this cake. The recipe stood out as a unique twist on a rhubarb dessert! Of course, I had to try it myself, and I have never tasted a rhubarb cake so crunchy and sweet. It is amazing.

A Moist And Tender Vanilla Cake Starts With Two Secret Ingredients

The “secret” ingredients aren’t a secret at all! They are buttermilk and vegetable oil. They are the dynamic duo when you want a moist, tender cake with a very fine crumb!

Buttermilk is acidic. It breaks down the gluten in the flour and tenderizes the cake crumb. Buttermilk also adds moisture and has a pleasantly tangy flavor that plays well with vanilla.

Oil makes cakes that stay moist longer than butter cakes because it remains a liquid at room temperature. The water in the butter evaporates, and cakes made with it can dry out more quickly.

All the rise in a cake made with these ingredients comes from loads and loads of teeny air bubbles created when acidic buttermilk meets alkaline baking soda. The crumb is very even, without any big air holes and a melt-in-your-mouth texture.

Put These Two Things On The Rhubarb Before You Start The Cake

rhubarb and sugar

Put one-half cup of sugar and a tablespoon of flour on the finely diced rhubarb and stir, then set it aside while making the cake. Thie sugar will start to draw the juices out of the rhubarb, and the flour will help keep it suspended in the batter while the cake bakes. This way, all the rhubarb won’t sink to the bottom.

Combine the sugar, oil, vanilla, baking soda, and egg, and beat the mixture until it’s creamy. Then add buttermilk and flour alternately and beat until well blended, scraping down the sides of the bowl a time or two.

Finally, fold the rhubarb into the batter, and put the mixture into the greased baking dish. Bake in a 350-degree oven for about thirty-five minutes but do not underbake. A toothpick inserted in the center of the cake should come out clean, and the cake should start pulling away from the sides of the pan.

If you underbake the cake, it can sink in the center. 😢 I may have learned this from experience. Don’t make the same mistake! LOL

Make The Yummy Four Ingredient Topping While The Cake Bakes

How can you go wrong with a mixture of coconut, pecans, butter, and brown sugar? There is no way.

Make the incredible topping when the cake is baking. In a heavy saucepan, combine the ingredients and bring them to a boil for three minutes, stirring constantly. Set aside while the cake finishes baking. Keep the topping warm by putting the lid on the pan.

When you take the cake out of the oven, let it sit on a cooling rack for a few minutes. Then, while the cake is still warm, spread that coconutty goodness carefully on top of the still-warm cake, coaxing it to the edges. It is as sweet and tasty as it looks!

This cake uses rhubarb, but rhubarb is not the star of the show in this rhubarb cake with coconut pecan topping recipe. The topping is what this cake is all about.

Are you looking for other rhubarb recipes? Here are some of our favorites. Magic Rhubarb Pudding Cake, Rustic Rhubarb Bread, Rhubarb Muffins With Streusel Topping. Too much rhubarb? Here’s how to freeze the extra!

If that’s not enough, type rhubarb in the search bar, and be prepared to stick around a while!😉

Printable Recipe:

Yield: 15 servings

Rhubarb Cake With Coconut Pecan Topping

rhubarb cake with coconut pecan topping

This recipe is for a dense, moist cake topped with brown sugar, butter, coconut, and chopped nuts, a very rich dessert for someone with a big sweet tooth!

Prep Time 15 minutes
Cook Time 35 minutes
Total Time 50 minutes



  • 1 1/2 cup diced rhubarb
  • 1/2 cup sugar
  • 2 cups flour
  • 1 1/2 cups sugar
  • 1 tbsp flour
  • 1 tsp baking soda
  • 1 cup buttermilk
  • 1 egg
  • 1/2 cup vegetable oil
  • 1 tsp vanilla
  • 6 Tbsp butter
  • 2/3 cup brown sugar
  • 1/4 cup milk
  • 1 cup flaked coconut
  • 1 cup chopped pecans


  2. Preheat the oven to 350 degrees
  3. Grease a 13" by 9" baking pan and set it aside
  4. In a small bowl, put 1/2 cup of sugar and one tablespoon of flour on diced rhubarb, stir, and set aside.
  5. Mix sugar, egg, vanilla, baking soda, and oil in a bowl and beat until creamy.
  6. Add flour and buttermilk alternately and beat until well blended.
  7. Fold the rhubarb into the batter and distribute it evenly.
  8. Pour the batter into the greased pan and bake for about 35 minutes or until a toothpick inserted in the center comes out clean. The edges of the cake should start to pull away from the sides of the pan. Do not underbake, or the center can sink.
  9. Put the baked cake on a rack to cool, but you will pour on the topping while the cake is still warm.
  11. While the cake is baking, combine all the ingredients in a heavy saucepan.
  12. Bring the mixture to a boil, constantly stirring, for three minutes.
  13. Pour the warm topping on the warm cake and carefully spread it to the edges of the cake.

If you enjoyed this recipe, please share it on your social media! I would love for more people to try this delicious and easy-to-make recipe. If you have any questions or feedback, please feel free to leave a comment below. I would love to hear from you! Shhh… Join our secret foodie group on Facebook

Rhubarb Cake With Coconut Pecan Topping
Rhubarb Cake With Coconut Pecan Topping

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  1. You forgot to say to add the rhubarb mixture into the cake batter before pouring it into the pan.

  2. Janice Sloan

    When do you add the baking soda? It’s listed in the ingredients but not mentioned in the instructions.

    • Thanks to your sharp eye, I did fix the narrative and the recipe. I add baking soda with the wet ingredients, I always have. I think it distributes it more thoroughly. You can also whisk it into the flour if you’d rather do it that way. Thanks for pointing it out. I did reply or thought I did. Sorry for the delay!!

  3. Janice Sloan

    When do you add the baking soda? It’s listed in the ingredients but not mentioned in the instructions.
    Yes I did. It it’s not in the comment section.

  4. Janice Sloan

    Great recipe by the way!!

  5. This looks amazing! Is there any way you can use a sugar substitute? My husband is diabetic but I would love to give this a try.

    • Darn it, I have very little experience with sugar substitutes, Jean. If I were in your shoes, I would do some research online for sugar substitutes that work for diabetics. Is there a grocery store close to you that has a dietician on staff or does your local hospital have someone you can talk to? I admire you so much for finding ways to keep your husband happy and healthy. I’ve been doing that myself for 52 years! ❤ good luck!!!


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