Rhubarb Cake with Butter Sauce

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Here’s a soft, old-fashioned Rhubarb Cake with Butter Sauce that’s as easy as can be—just one bowl, a quick stir, and bake it all in a 9 x 13 pan. It’s a lovely recipe to bring to potlucks or pack up for a sunny picnic.
This cozy dessert pairs beautifully with our Easy Rhubarb Crisp Recipe.

Tangy, fresh rhubarb pairs beautifully with a sweet Butter Cream Sauce in this cake. It’s a fun twist on the classic cranberry cake with butter sauce that often makes an appearance around the holidays.

For a fresher spring vibe, I swapped out cranberries for rhubarb. Since both have that wonderful tang, this cake strikes the perfect balance between tart fruit and rich, buttery sauce.

How To Make An Old Fashioned Rhubarb Cake

This rhubarb cake with butter sauce comes together easily in one bowl and creates a soft, comforting homemade dessert with classic old-fashioned flavor.

This cake doesn’t use any eggs, which means it comes together quickly in one bowl. Start by sifting the dry ingredients—flour, sugar, baking powder, and a pinch of salt.

Next, fold in the milk, melted butter, and diced rhubarb gently. Pour the batter into your greased pan, and bake. That’s it!

I love how quickly this dessert comes together—just like a box mix but tastes completely homemade and so much better. You probably have all the ingredients in your pantry, except the rhubarb, of course.

This Rhubarb Cake is a lifesaver for those days when you have unexpected guests or need to bring something delicious and homemade to a potluck without spending much time in the kitchen.

The egg-free formula means this cake stays tender and soft, which is exactly how I like it. Just be careful not to overbake it, so it doesn’t dry out. If it does, a generous drizzle of the buttery sauce will bring it right back to moist heaven.

This soft, egg-free rhubarb cake comes together in one bowl and bakes beautifully in a 9 x 13 pan—no fancy tools needed. It’s a simple mix of everyday pantry staples combined with bright, tart rhubarb and finished with a delicious warm butter sauce. It’s perfect for potlucks, picnic treats, or when you just want something homemade without the fuss.
For another cozy homemade treat, check out our Moist Cinnamon Rhubarb Bread.

Expect a tender crumb with a subtle tang from the rhubarb. It’s especially dreamy served warm with a big drizzle of that luscious butter sauce. The batter is a breeze—no eggs or complicated steps—and the sauce whips up in no time. This recipe makes about 15 generous servings, so you can feed a whole crowd.

For timing, plan on about 15 minutes to prep, 45 minutes baking, and about an hour to cool before serving. You can use fresh rhubarb or frozen that’s been thawed. Plus, you can make the sauce ahead and reheat when you’re ready, or even bake the cake a day early and warm it up gently. Super flexible!

Bright, tart rhubarb meets warm, buttery sauce in this old-fashioned, one-bowl cake that’s easy and nostalgic. We’re swapping rhubarb for the usual cranberries to bring a fresh spring twist to this classic butter-sauce cake—made with simple pantry staples, no eggs, and baked in one 9 x 13 pan that’s made to serve a crowd.
If you love rhubarb desserts, you should also try our Classic Strawberry Rhubarb Pie.

You’ll get a tender crumb with just the right tang that’s irresistible when warm and topped with a generous pour of buttery cream sauce. The batter mixes up in about 15 minutes, the cake bakes for roughly 45 minutes, and including cooling time, it’s ready to serve in about 2 hours. The recipe yields about 15 hearty servings and works with fresh or thawed frozen rhubarb.

Make it the day before and rewarm, or keep the sauce separate and heat it just before serving. Scroll down for the full ingredient list, easy step-by-step instructions, plus tips for customizing and storing.

• Hands-on time: ~15 minutes
• Bake time: ~45 minutes
• Total time: ~2 hours (including cooling)
• Makes: about 15 servings in a 9 x 13 pan
• Highlights: one-bowl, egg-free, freezer-friendly, easy to tweak

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Why You’ll Love This Rhubarb Cake with Butter Sauce

This rhubarb cake with butter sauce is soft, nostalgic, easy to make, and perfect for spring gatherings, potlucks, and cozy homemade desserts.

What Makes This Cake Special

This cake is simple, nostalgic, and full of classic homemade flavor. It’s quick to mix, delicious, and meant to share. If you want a dessert that’s simple, crowd-pleasing, and full of classic comfort, you’ll love this one.

• Simple one-bowl preparation. Whisk the dry ingredients, stir in milk, melted butter, and diced rhubarb, then bake in a 9 x 13 pan.
• Egg-free for tender texture. Without eggs, this cake stays soft and comforting with a lovely crumb. Just watch the bake time so it doesn’t dry out.
• Balanced sweet and tart flavor. The tangy rhubarb shines alongside the rich, sweet butter sauce. That sauce, made from butter, sugar, and cream boiled just a minute, is like a fancy frosting you can pour on—it’s addictive.
• Feeds a crowd easily. Made in one big pan with about 15 servings, this cake is ideal for potlucks, picnics, or when surprise guests drop by.
• Flexible to customize. Use fresh or frozen rhubarb (just thaw and drain), swap half the rhubarb for strawberries or mixed berries, add cinnamon or nutmeg, sprinkle with streusel, or halve the recipe for a smaller pan. It plays well with changes.
• Make-ahead friendly. Bake a day ahead and gently rewarm before serving. The butter sauce stores well in the fridge and heats up beautifully.
• Minimal pantry staples. No fancy ingredients needed other than rhubarb, making it budget-friendly and easy to pull together on a busy day.

This is a true old-fashioned rhubarb cake—eggless, one-bowl, wonderfully simple. The rhubarb adds that fresh tang to the soft cake, and the warm butter sauce brings a rich, nostalgic finish.

Cake and Butter Sauce Ingredients

These simple pantry ingredients create the perfect rhubarb cake with butter sauce with a tender crumb and rich buttery topping.

• 4 cups all-purpose flour
• 2 cups granulated sugar
• 4 teaspoons baking powder
• 1/2 teaspoon salt
• 4 cups rhubarb, diced (see note about frozen rhubarb below)
• 2 cups milk
• 6 tablespoons butter, melted
• 1/2 cup (1 stick) butter
• 1 cup granulated sugar
• 3/4 cup heavy cream

Make the Cake and Butter Sauce

Making rhubarb cake with butter sauce at home is easier than you think and perfect for beginner bakers.

1. Preheat the oven to 350°F (175°C).
2. Grease a 9 x 13-inch baking pan or line it with parchment paper.
3. If using frozen rhubarb, thaw completely and drain; if using fresh, dice the rhubarb.
   Here’s a helpful guide on how to prepare fresh rhubarb.
4. In a large bowl, whisk together the flour, granulated sugar, baking powder, and salt until well combined.
5. Melt the butter for the batter and set it aside.
6. Fold the diced rhubarb, milk, and melted butter gently into the dry ingredients, stirring just until moistened.
7. Pour the batter into the prepared pan and smooth the top evenly.
8. Bake about 45 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs.
9. Remove the cake from the oven and let it cool while you make the sauce.
10. In a heavy saucepan, combine the butter, granulated sugar, and heavy cream for the butter sauce.
11. Heat the sauce over medium, bring it to a boil, and let it boil for 1 minute while stirring constantly.
12. Remove the sauce from the heat and let it cool slightly to thicken.
13. Cut the cooled cake into squares and drizzle with warm butter sauce, reheating the sauce gently if it cools too much.
    Serve this cake alongside our Easy Rhubarb Compote for an extra fruity touch.

Tips for a Tender, Moist Cake

• Measure flour by spooning it into your cup and leveling off instead of scooping or packing it down. This keeps your cake from ending up too dense.
• Stir the batter gently—just mix until the flour is moistened. Overmixing can toughen the cake’s crumb.
• Keep a close eye when baking. Without eggs, this cake can dry out if left in too long. Use a toothpick test: it should come out clean or with a few moist crumbs.
• If using frozen rhubarb, thaw it fully and drain well, but avoid squeezing to keep the texture right.
• Always warm the butter sauce before serving. It makes sure the cake stays moist and adds a silky richness that totally elevates every bite. Warm slowly on the stove or microwave in short bursts, stirring in between.
• Grease your pan really well or line it with parchment paper so you get neat slices and easy removal.

Mix-Ins and Flavor Swaps

One of the best things about rhubarb cake with butter sauce is how easy it is to customize with berries, spices, and crunchy toppings.

• Mix in 1 teaspoon cinnamon or 1/2 teaspoon nutmeg with the dry ingredients to add a cozy, warm spice note.
• Stir 1 teaspoon vanilla extract into the batter or swirl it into the warm butter sauce for extra flavor depth.
• Try swapping half the rhubarb for chopped strawberries or frozen mixed berries for a fruity twist.
• For a crunchy topping, sprinkle a streusel made from butter, flour, brown sugar, and oats over the batter before baking.
• If you prefer a lighter sauce, replace half the heavy cream with whole milk—the sauce will be thinner but still delicious.

Storing, Freezing, and Reheating

Properly stored rhubarb cake with butter sauce stays soft, moist, and delicious for several days.

• Room temperature: Keep the cake covered on the counter for up to 2 days. Store the butter sauce separately if you can.
• Refrigerator: Cover and chill the cake for up to 4 days. Store butter sauce in an airtight container in the fridge for 4–5 days. Rewarm gently before serving.
• Freezing: The cake (without sauce) freezes beautifully. Wrap pieces tightly in plastic wrap and foil, freeze up to 2 months. Thaw overnight in fridge and warm briefly before serving. The butter sauce can be frozen but might change texture—best fresh or refrigerated and reheated.
• Make-ahead: Bake the cake a day ahead, then warm gently in a low oven (about 300°F/150°C) before serving. Reheat the sauce separately on the stove until smooth and warm.

Final Thoughts on This Rhubarb Cake with Butter Sauce

This rhubarb cake with butter sauce is soft, buttery, tangy, and perfect for spring and summer baking. The warm butter sauce makes every bite rich, comforting, and completely irresistible.

Common Questions and Answers

• Can I use frozen rhubarb? Absolutely! Just thaw it fully and let any extra liquid drain naturally. No squeezing needed. Then use it in the recipe as usual.
• Is this cake egg-free? Yes! This cake skips eggs, which helps keep it tender and soft, and gives it that classic old-fashioned texture.
• Can I halve the recipe? Yes, all the ingredients scale down easily. Use a smaller pan and watch your baking time—it will be shorter.
• How do I know when the cake is done? Insert a toothpick in the center. It should come out clean or with a few moist crumbs. Avoid baking it until completely dry to keep it soft.
• Can I make the butter sauce ahead? Yes! Make it ahead and store in the fridge. Gently reheat before serving—it warms up silky and smooth.
• Can I substitute oil for butter in the cake? You can try a neutral oil, but butter adds really important flavor and texture here. Swapping it might change the cake’s taste and crumb.