Fudgy White Chocolate Rhubarb Blondies

June 16, 2022

Highlight one of the earliest fruits of summer in these sweet, tart, and fruity bite-sized delights. White chocolate rhubarb blondies are fudgy and chewy, with the perfect pop of brightness.

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We got our first farm share shipment of the year this week, and I am just bursting with the excitement of having a fridge packed full of fresh, local produce. One of the earliest crops every year is rhubarb. This unique, tart stalk gets pigeonholed as a partner to strawberries, but it’s been growing on me as a solo act.

In this recipe, rhubarb may be the only fruit, but the resulting white chocolate blondies are definitely fruity. They are also sweet, fudgy, and chewy, thanks to the white chocolate base that I love using for these delectable bites.

What You Need to Get Started

You can easily find all of the ingredients for these fudgy white chocolate rhubarb blondies at your grocery store:

Let’s Make Fudgy White Chocolate Rhubarb Blondies

These blondies are about to become your favorite dessert to make. The effort-to-reward ratio on these babies is excellent. One-bowl, no mixer, super simple technique. And in the end you get flaky-topped, fruit-filled, chewy blondies. Honestly, you can’t lose.

Since the batter for these comes together so fast and easily, it’s a good idea to get your oven preheated and a square baking pan lined with parchment paper before you even get started.

Then, it all begins with melting some white chocolate chips. This blondie recipe is based on my favorite fudgy one-bowl brownies, except that I use white chocolate instead of dark for the base. You can use white chocolate baking bars here instead of chips, but I find the chips to be more affordable and easier to find.

Add the white chocolate to a large mixing bowl that is microwave safe, along with both butter and vegetable oil. You’ll want to melt the white chocolate but not scald it, so zap it in thirty second increments, stirring between each until it’s nice and smooth.

Sometimes, a few stubborn chips will hold their shape, but the residual heat of the warmed oil and butter will help them melt.

Mix in some sugar next. We’re sticking with only granulated sugar in these, since they are blondies. I usually use a mix of white and brown sugar in my brownies, but here, I like adding fewer extra flavors into the whole mix. The heat should help the sugar dissolve slightly, and you will be able to mix it until fairly smooth.

If the bowl still feels pretty warm once the sugar is added, set it aside for about five minutes to cool slightly. That’s because the next step is to add in the eggs, and scrambled egg blondies are not what we’re going for here.

Mix in the three eggs and some vanilla extract. I know, I just said I’m trying not to have too many flavors here, but I find that the vanilla actually helps to accentuate the white chocolate flavor, not detract from it.

As for the eggs, they are the main structure of your blondies. I think of these bite-sized bars as falling halfway between cookie bars and a flourless torte. So the eggs are pretty important for holding it all together.

However, unlike the torte, these do contain some flour. It’s not a ton, just a small amount to really give them that perfect brownie texture. Too much flour, and you end up with cakey blondies instead.

Now it’s time to fold in some fresh rhubarb. If you are able, get your rhubarb stalks from a local farm when they are in season. That’s when you’ll end up with the best flavor, and they will be the most affordable.

Otherwise, be sure to look for firm stalks that are not too thick or woody, and definitely not wilted. When choosing rhubarb, the color doesn’t really indicate the flavor. Sometimes, the red skin can be a bit tougher to cut through, so I usually just pull off those stubborn pieces while chopping.

If your stalks are wide, halve them longways first, and then dice the rhubarb into quarter- to half-inch pieces. Use a folding motion to distribute them evenly throughout the batter. It should be thick enough that the pieces are well suspended.

Grab that baking pan you lined with parchment earlier, and transfer the batter into it. Be sure to use a flexible spatula to scrape all of that white chocolate rhubarb goodness out of the mixing bowl and into the pan.

Then use that same spatula to spread the batter into the corners and edges of the pan, creating an even layer. Smooth out the top, but don’t worry too much about it looking perfect.

Now scatter a handful of extra white chocolate chips over the top of the blondie batter. If you prefer, you can press these into the batter a little bit, or just let them sit on top. Either way, they’ll sink into the blondies slightly when they bake.

That was easy, right? Now bake the blondies for forty-five minutes or so. It’s a nice, long time, so feel free to relax and grab a cocktail. Stick with the theme and try a birthday cake martini, which also has some white chocolate flavor.

You’ll know the blondies are ready when the top is a flaky golden color, the edges have browned somewhat, and a butter knife inserted into the center comes out clean. I find that a toothpick will sometimes be clean a little early, so the butter knife is a better tester in this case.

Let the blondies cool completely in the pan, resting on a trivet. This can take a few hours, or you can even leave them overnight. I definitely suggest baking these the day before you want to serve them, so there’s plenty of time for them to cool.

Use the parchment paper to gently lift the blondies out of the pan, and place them on a flat work surface for cutting. A good serrated knife, like a cake knife, works well for cutting these blondies into sixteen pieces.

If you are transporting these or not serving them all at once, you can use the parchment paper again to lift the blondies back into their original pan after cutting them. You can store these, covered tightly, at room temperature for a few days.

For longer-term storage, they can also be frozen for a couple months. Be sure to wrap them, cut or uncut, tightly in plastic wrap. Before serving them, let the frozen blondies thaw until they reach room temperature.

Rhubarb’s going solo in these super fudgy white chocolate rhubarb blondies. Feature the sour early summer stalk in a decadent bite-sized dessert!

How to Serve White Chocolate Rhubarb Blondies

I’m calling it now: blondies are the official dessert of summer. They are just as sweet, delicious, and chewy as brownies, but with a lighter flavor. And the rhubarb in these makes them an excellent seasonal treat for your next cookout or party. For the full summer experience, be sure to pair them with a refreshing glass of rhubarb hibiscus pink lemonade.

The perfect way to present these blondies is to make them part of a fruity dessert bar. Try serving them alongside any combination of lemon cupcakes with lavender-chamomile frosting, blueberry cheesecake cookies, mandarin orange posset tart, and cherry cheesecake napoleons. To make them the star, warm each blondie, and serve with a scoop of strawberry ice cream.

Or you could make these sweet little bites the stars of happy hour! Serve them on miniature plates with delicious cocktails like raspberry margaritas, watermelon daiquiris, or a big pitcher of dragon fruit rose sangria, to show off that pretty pink rhubarb color.

Use Up Leftover Ingredients

More Brownies, Blondies, and Bars

Fudgy White Chocolate Rhubarb Blondies

Chewy blondies made with white chocolate chips, packed with fresh rhubarb pieces for a sweet and fruity treat.
Prep Time15 minutes
Cook Time50 minutes
Total Time1 hour 10 minutes
Course: Dessert
Cuisine: American
Servings: 16 blondies
Calories: 212kcal


  • 4 Tbsp Butter
  • ¼ Cup Vegetable Oil
  • 9 oz White Chocolate Chips plus a few extra for topping
  • ¾ Cup Granulated Sugar
  • ½ tsp Vanilla extract
  • 3 Eggs
  • Cup Flour
  • 1 ½ Cups Rhubarb diced into ¼- to ½- inch pieces


  • Preheat the oven to 350°F with a rack in the center, and line an 8x8 pan with parchment paper overhanging the edges.
  • Add the white chocolate chips into a medium microwave-safe bowl, along with the butter and oil. Heat in 30 second increments, stirring after each until smooth.
  • Whisk in the sugar, and set the bowl aside to rest for 5 minutes to cool slightly. Then add in the vanilla and eggs and stir until thoroughly combined.
  • Add in the flour, and mix it into the liquids thoroughly. Then fold in the rhubarb until distributed.
  • Transfer the batter to the prepared pan, and use a spatula to spread it around into the corners, and even out the top. Scatter with additional white chocolate chips as desired.
  • Bake for 45-55 minutes, until a butter knife inserted into the center comes out clean. If the top is getting too dark, cover the pan loosely with foil.
  • Allow to cool completely in the pan on a trivet. Then use the parchment paper to carefully remove the blondies and slice. Serve at room temperature.


Make ahead tip: These blondies store well in a sealed container at room temperature for 3-4 days. You can also freeze them for 2 months. Wrap the blondies, cut or uncut tightly in plastic wrap and foil. Allow frozen blondies to thaw to room temperature before serving.

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