Dark Chocolate Rhubarb Brownies Recipe

Brownies are a firm favorite on restaurant dessert menus, as well as with home bakers and it is no wonder why. Invented in Chicago, these gooey, rich, chocolatey delights truly are one of the Windy City's best gifts to the world. Nowadays there are countless recipes that take the classic brownie and add delicious, innovative spins. Some call for a special extra ingredient, while others entail the use of a special technique to create new versions of one of the world's most loved desserts. 

One thing is for sure: You could find a different brownie recipe for every day of the year, and what a year that would be! In this recipe, Tasting Table recipe developer Jennine Rye uses dark chocolate, tangy rhubarb, and hazelnuts to make a richly flavored brownie that is perfect for those who love their brownies packed full of flavor and texture. While rhubarb is not an ingredient commonly seen in brownies, it pairs beautifully with the depth of dark chocolate and takes the humble and ever-delicious brownie to new culinary heights. So if you are looking for a baked product that everyone will love, why not indulge in these delicious brownies? Quick to make and sure to impress, read on to find out how easy it is to make these fudgy, rich brownies yourself at home. 

Gather the ingredients for dark chocolate rhubarb brownies

To make this recipe for dark chocolate rhubarb brownies, first, you will want to gather the ingredients. For the basic brownie batter mix you will need dark cocoa powder, plain flour, salt, melted butter, granulated sugar, light brown sugar, some eggs, and vanilla extract. Then, to give the brownies a bit of texture and a whole lot more flavor and excitement, you will need some diced rhubarb, dark chocolate chips, and chopped hazelnuts. If you want to mix things up a little more, you can try swapping out the hazelnuts for pecan nuts or the dark chocolate chips for white chocolate instead.

Begin the brownie batter

To make these brownies extra fudgy and delicious, Rye starts by mixing the butter (warm and melted) with the sugar until it is smooth and glossy and no longer grainy. Although brownie recipes often use oil, using butter instead of a vegetable oil results in brownies that will be much more flavorsome and deliciously moist. 

How much you mix your brownies is just as important as the ingredients that go into them to determine the resulting texture. It stands to reason that adding too much flour will leave you with drier brownies, but so too can over mixing the batter. Mixing the ingredients by hand might be a little more tiring for your arm, but will allow you to keep a close eye on the batter and you will be able to stop as soon as the ingredients are blended together, avoiding the perils of over-mixing and resulting in lovely squidgy brownies.

Finish the batter

Next up it's time to add the eggs and vanilla extract. As before, whisk the ingredients by hand to avoid an overly mixed batter (and tough brownies). By combining the dry ingredients separately you can reduce the amount of time needed to mix the batter all together, so use a separate bowl to whisk together the flour, cocoa powder and salt. Then fold this blend of dry ingredients into the mixture of butter, sugar eggs and vanilla extract using a wooden spoon, until the dry ingredients are just combined. You want to end up with a batter which is smooth, dark and beautifully glossy.

Add the mix-ins and bake

When the batter is complete, it is time to add the chopped rhubarb, the dark chocolate chips, and the hazelnuts, and gently fold them into the batter. 

Pour the batter into a baking tray lined with baking paper, and then bake in the oven. Expect the baking to take about 20–25 minutes, but remember that cooking times can vary slightly depending on your individual oven. To make sure your brownie is ready to come out of the oven, gently insert a skewer into the inner part of the brownie. If, when you pull it back out, there is still a little moist batter on the skewer, you have achieved optimal fudgy brownie texture and it is ready to come out and cool.

While it's tempting to tuck straight in, you'll need to let brownies cool completely before cutting and serving them. To cut through the richness of the brownies and the delicious tang of the rhubarb, they can be paired with a little pouring cream, a lashing of whipped cream, or a scoop or two of ice cream.

Dark Chocolate Rhubarb Brownies Recipe
4.9 from 70 ratings
Rhubarb is a surprising ingredient in this brownie, but the fruit's tart flavor pairs so well with the dark chocolate and hazelnuts in this recipe.
Prep Time
Cook Time
Dark chocolate rhubarb brownie
Total time: 35 minutes
  • ¾ cup dark cocoa powder
  • ⅓ cup plain flour
  • ½ teaspoon sea salt
  • ⅔ cup butter, melted
  • ½ cup granulated sugar
  • ¾ cup light brown sugar
  • 2 large eggs, room temperature
  • 1 tablespoon vanilla extract
  • 1¼ cups diced rhubarb
  • ¾ cup dark chocolate chips
  • ⅓ cup chopped hazelnuts
  1. Preheat the oven to 350 F and line an 8x8-inch baking pan with baking paper.
  2. Whisk together the dark cocoa powder, the plain flour, and the sea salt. Set to one side.
  3. In a large bowl, whisk together the melted butter with the granulated sugar and the light brown sugar until it is thoroughly combined, and looks smooth and glossy.
  4. Whisk in the 2 eggs and the vanilla extract.
  5. Fold the dry mixture into the wet mixture using a wooden spoon until it is just combined.
  6. Add the diced rhubarb, the dark chocolate chips, and the chopped hazelnuts, and gently fold them in, being careful to not over-mix the batter.
  7. Transfer the batter to the prepared baking tray, smooth it out, and then place into the oven to bake for 20–25 minutes.
  8. Remove from the oven when a skewer inserted into the brownie comes out coated with a little moist batter, and then allow the brownie to sit and cool completely before cutting and serving.
Calories per Serving 384
Total Fat 24.8 g
Saturated Fat 13.3 g
Trans Fat 0.0 g
Cholesterol 77.9 mg
Total Carbohydrates 39.4 g
Dietary Fiber 5.1 g
Total Sugars 27.2 g
Sodium 131.2 mg
Protein 5.4 g
The information shown is Edamam’s estimate based on available ingredients and preparation. It should not be considered a substitute for a professional nutritionist’s advice.
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