Dark Chocolate Rhubarb Brownies
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Chocolate rhubarb brownies are a rich and decadent treat that has the best slightly tart flavor of rhubarb which cuts through the sweetness like magic. They’re moist, fudgy, and sweet with chocolate chips and walnuts and just the right amount of rhubarb flavor. You’ll love them!
This is the brownie recipe we make every spring. The best part of these brownies is the little bits of moist rhubarb. They’re not overly tart like you’re probably thinking. It’s the texture that I really amazing. Rhubarb does for these brownies what carrots do for carrot cake. Trust us, it just works.
But the rhubarb flavor is in every bite, too. And again, it just works. The tartness of the rhubarb marries perfectly with the sweet brownies. Don’t expect these brownies to last long; they’re delicious!
How to make rhubarb brownies
Most brownie recipes are pretty straightforward, and this one is no exception. In fact, it’s one of the easier ones. Here’s what you’re going to do:
- Whisk the wet ingredients in a bowl.
- Now whisk the dry ingredients in another bowl.
- Then combine them together and stir in the rhubarb, chocolate chips, and walnuts.
- Scrape the batter into a parchment paper-lined baking dish then put the brownies into your oven.
The hardest part of making this recipe is waiting for the brownies to cool before you cut into them!
How to make extra-thick brownies
Sometimes nothing but extra-thick brownies will do. If that’s what you’re craving, increase the recipe by half. Here are the measurements:
1 ½ cups sugar, ¾ cups vegetable oil, 3 eggs, 1 ½ teaspoons vanilla, ¾ cup flour, 1/3 cup + 3 tablespoons cocoa powder, ¾ teaspoon baking powder, ¾ teaspoon salt, 1 ½ cups rhubarb, ¾ cup chocolate chips, ¾ cups chopped walnuts.
For extra-thick rhubarb brownies, bake for an additional 5 minutes.
Can I make these without gluten?
Yes! Several readers have reported success using both a gluten-free flour mix and almond flour.
How long do rhubarb brownies last?
Not long around here! Ha! If you have any left an hour after they come out of the oven, they will keep well in a covered container at room temperature for 3-4 days.
Can rhubarb brownies be frozen?
Yes! These brownies freeze very well. Cool them completely before you put them into your freezer. We like to freeze them wrapped individually so we can take out a few at a time. Let them thaw at room temperature before eating them.
Chocolate Rhubarb Brownies Recipe
Ingredients
- 1 cup granulated sugar
- ½ cup vegetable oil
- 2 large eggs
- 1 teaspoon vanilla
- ½ cup all-purpose flour (can sub gluten-free or almond flour)
- ⅓ cup cocoa powder
- ½ teaspoon baking powder
- ½ teaspoon sea salt
- 1 cup rhubarb (diced small)
- ½ cup dark chocolate chips
- ½ cup chopped walnuts or pecans
Instructions
- Preheat your oven to 375 degrees. Line an 8×8 inch baking pan with parchment paper and lightly butter the top.
- In a medium-sized bowl, whisk the sugar, vegetable oil, eggs, and vanilla.1 cup granulated sugar, ½ cup vegetable oil, 2 large eggs, 1 teaspoon vanilla
- In a large bowl, whisk the flour, cocoa powder, baking powder, and sea salt.½ cup all-purpose flour, ⅓ cup cocoa powder, ½ teaspoon baking powder, ½ teaspoon sea salt
- Stir the wet ingredients into the dry ingredients and mix them until they are just incorporated. Add the rhubarb, chocolate chips, and nuts and mix until they are combined. The batter will be quite thick.1 cup rhubarb, ½ cup dark chocolate chips, ½ cup chopped walnuts or pecans
- Pour the batter into the prepared baking dish and spread it out so that it is even. Bake for 20-25 minutes, or just until a toothpick inserted into the middle comes out clean – see notes. Make sure not to overcook the brownies so they don't dry out.
- Remove the brownies from the oven and let them cool for at least 10 minutes. Cut them into 9 squares and … try not to eat them all at once!
Video
Notes
Nutrition
We have thoroughly tested this recipe for accuracy. However, individual results may vary. See our full recipe disclosure here.
For more inspiration, check out all of our dessert recipes!
I used coconut oil instead of vegetable oil and got rave reviews. 10/10!
Love hearing that! Coconut oil is a great swap—it adds such a nice flavor. So glad it was a hit and got rave reviews!
The recipe calls up vegetable oil. There are a lot of oils loosely classified as vegetable oil. The first time I made the these brownies I used peanut oil. They tasted terrific but were very fragile, more like a dessert.
The next time I used extra virgin coconut oil and they were firm but not as tasty to me. I guess individual preferences come into it.
Then I made a batch with half and half of the peanut & the extra virgin coconut oil but that result was a bit strange. The lower part was firm and the upper part fragile.
What specific vegetable oil did you base your recipe on?
Thanks so much for your thoughtful comment—I love hearing about all your experimenting! You’re totally right: “vegetable oil” is a broad term, and different oils can definitely affect both texture and flavor.
When I developed the recipe, I used avocado oil, which keeps the brownies moist and rich without adding any strong flavor. It helps give them that classic fudgy texture with just enough structure to hold their shape.
Your versions sound like a delicious science experiment! I’d say go with whatever combo gives *you* the perfect brownie bite! 😊🍫
This is the 3rd time I have made this. Instead of vegetable oil I used butter 🧈. So tasty. Finish it off with some cream.
Great idea with the butter! Yum!
Really good brownie and the rhubarb makes it perfect 🥰 it is very delicious and easy to make 😃
Thanks so much, Kristin!
They were tasty and easy to make! Why after cooling completely could I not get a clean cutting? I even dipped my knife in water. Should I have cut them while warm?
I’m glad you enjoyed the recipe! I find that the best way to cut brownies with clean edges is to let them cool completely (like you did), then use a chef’s knife (not serrated) and run it under hot water between each slice. Cut straight down and then pull the knife up – rather than dragging it through the brownies. I hope that helps!
The most decadent brownies ever – used olive oil vs. veg.oil, used toasted pecans vs. walnuts, 2x recipe in 9×13 pan, used 3 duck eggs vs. 4 chicken eggs, Hersey’s cocao pwdr, Ghiradelli 60% Dark chips, fresh from the garden rhubarb. 45 min. baking time.
Oh. So. Worth. It!
Thank you Kristen!
You’re welcome, Deborah!!