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This is a soft, old-fashioned Rhubarb Cake with Butter Sauce: a simple one-bowl cake to stir together and bake in a 9 x 13 pan. This is perfect for a potluck or picnic.

Tangy Rhubarb Cake with Sweet Butter Sauce

Rhubarb Cake with Butter Sauce

Tangy Rhubarb Cake becomes completely irresistible when paired with the sweet Butter Cream Sauce. This cake is a twist on a classic Christmas dessert, cranberry cake with butter sauce.

I’ve updated it for spring and substituted rhubarb for the cranberries. It works so well, as both cranberries and rhubarb are tart and pair well with the butter sauce.

How To Make An Old Fashioned Rhubarb Cake

This is an egg-less cake which makes it super easy to make in one bowl. First, you’ll sift all the dry ingredients together. They are just the basics: flour, sugar, baking powder, and salt.

To that mixture you’ll gently stir in the milk, melted butter and diced rhubarb. Pour into a pan and bake.

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Classic Rhubarb Cake

This is seriously the easiest dessert. It’s just as fast as using a cake mix and doesn’t require and special ingredients (other than rhubarb, of course.)

The Rhubarb Cake is perfect for last minute company or anytime you want to bring a dessert somewhere. 

The lack of eggs in this cake makes it especially tender and I love that. Be careful not to over bake it as it will be dry. Don’t worry though, a healthy dose of butter sauce will fix it. 

Rhubarb Cake with Butter Sauce

How To Make Butter Sauce

Butter sauce is just butter, heavy cream and granulated sugar – and it is oh, so delicious when poured warm on cake. Think of it as a superior frosting since frosting is just sugar and butter too. 

In a small saucepan, melt the butter, stir in the heavy cream and sugar, bring to a boil and boil for 1 minute.

Ta da, magic butter sauce that is perfect over cake.

In addition to seeing this butter sauce over cranberry cake, I’ve also seen it served over a Pecan Praline Cake and a Warm Gingerbread Cake.

Rhubarb Cake with Warm Butter Sauce

More Rhubarb Recipes

Both my family and my reader’s love rhubarb recipes. If you’re looking for ways to use up extra rhubarb, check out one of my other rhubarb recipes. 

Can I Freeze Rhubarb?

Rhubarb season is short, but never fear, you can use freeze rhubarb and use it throughout the year without any issues at all. You can also purchase frozen rhubarb at most grocery stores.

To use frozen rhubarb: thaw the rhubarb first and let any excess liquid drain off. Don’t squeeze any liquid out, just drain what naturally thaws out of the rhubarb. 

4.26 from 39 votes

Rhubarb Cake with Butter Sauce

Avatar photoMary Younkin
Old fashioned rhubarb cake with butter sauce. This rhubarb cake is made in a 9 x 13 pan and is a perfect easy dessert for a potluck or picnic.
Prep Time: 15 minutes
Cook Time: 45 minutes
Additional Time: 1 hour
Total Time: 2 hours
Servings: 15 servings
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Ingredients 

For the cake

  • 4 cups all-purpose flour
  • 2 cups granulated sugar
  • 4 teaspoons baking powder
  • 1/2 teaspoon salt
  • 4 cups rhubarb diced (see note below about using frozen rhubarb)
  • 2 cups milk
  • 6 tablespoons butter melted

For the butter sauce

  • 1/2 cup 1 stick butter
  • 1 cup sugar
  • 3/4 cup heavy cream

Instructions 

  • Preheat oven to 350° F. In a large bowl, whisk together the flour, sugar, baking powder and salt. Add the diced rhubarb, milk and melted butter. Stir just until combined.
  • Pour the batter into a greased 9 x 13 inch baking pan. Bake for 45 minutes or until a toothpick inserted comes out clean.
  • Remove from the oven and cool
  • To make the butter sauce, combine the butter sugar and cream in a heavy saucepan. Bring to a boil over medium heat and boil for 1 minute stirring frequently. Remove from heat and let cool slightly.
  • To serve, cut pieces of cake and serve with a generous amount of warm butter sauce. The sauce can be gently reheated on the stove or in the microwave if necessary.

Notes

To use frozen rhubarb: thaw the rhubarb first and let any excess liquid drain off. Don’t squeeze any liquid out, just drain what naturally thaws out of the rhubarb. 
Cranberry Cake recipe adapted from A Farm Girl Dabbles.

Nutrition

Serving: 1 piece | Calories: 363 kcal | Carbohydrates: 58 g | Protein: 4 g | Fat: 13 g | Saturated Fat: 8 g | Polyunsaturated Fat: 4 g | Cholesterol: 37 mg | Sodium: 257 mg | Fiber: 1 g | Sugar: 34 g

Nutrition information is automatically calculated, so should only be used as an approximation.

{originally published 4/20/19 – recipe notes and photos updated 5/6/21}

Tangy Sweet Rhubarb Cake with Butter Sauce
Rhubarb Cake with Butter Sauce

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Recipe Rating




111 Comments

  1. Jody says:

    2 stars
    I thought I’d love this, but all I taste is sweetness — not rhubarb.

    1. Mary says:

      Sorry to hear that it wasn’t a hit with you, Jody.

  2. Kathy says:

    5 stars
    This recipe is great. The butter sauce makes it. I use 2 round cake pans. One to keep at home and one to share at work.

    1. Mary says:

      I’m thrilled that you are enjoying the cake, Kathy.

      1. Tiffany says:

        3 stars
        I just made this and I was kind of disappointed. I was hoping for something a little lighter on the cake side. It tasted like flour.

        1. Mary says:

          I’m sorry to hear that, Tiffany. I don’t notice a pronounced flour flavor in this cake. Did you by chance substitute any ingredients?

  3. Linda Fisher says:

    For the butter sauce, is it granulated or powdered sugar?

    1. Mary says:

      That’s regular granulated sugar, Linda. Enjoy!

  4. Patsi says:

    Can I cut this recipe in half?

    1. Mary says:

      That should work fine, Patsi.

  5. Patty says:

    Just whipped this up. In the oven as I type. There was no pouring batter into the pan. It was very stiff. Then needed to spread it out into the 9×13 pan. Fingers crossed it works out, time will tell!

    1. Mary says:

      I hope you love it, Patty!

      1. Patty says:

        Was it to be a very stiff batter? Well I liked it…it tasted like a shortcake I make for strawberries…I’m thinking if I make this again…I will pour the butter sauce all over the cake when it comes out of the oven!

  6. Taylor says:

    5 stars
    This recipe screams Summer! I especially love the butter sauce!

  7. Becky Hardin says:

    Oh yum!!! This looks so amazing.

  8. Katerina @ diethood .com says:

    Such an incredible cake!! I would love a slice of this!

  9. Jen says:

    Rhubarb is such a favorite of mine and totally takes me back to my childhood. This cake sounds amazing and I can’t wait to take my first bite!

  10. Beth Pierce says:

    This sounds so decadent; that butter sauce makes the dish! Yum!

    1. Stephanie says:

      Do you use salted or unsalted butter ?

      1. Mary says:

        I use salted butter, Stephanie.