These rhubarb blondies have the classic butterscotch flavour and chewy texture of blondies, with chunks of white chocolate and swirls of rhubarb compote.
Why I love these rhubarb blondies!
- These rhubarb blondies are an easy one-bowl recipe that starts with melted butter, so no butter to soften!
- The easy rhubarb compote can be made ahead and can be made with fresh or frozen rhubarb.
- These delicious squares freeze beautifully, too.
Ingredients and substitutions
A few notes about the key ingredients …
Rhubarb – you can use either fresh or frozen rhubarb for these rhubarb blondies.
Red Food Colouring – I added some red food colouring to the rhubarb compote, to give it a brighter red colour. This is optional and it will still taste the same if you decide to omit it.
White Chocolate – the white chocolate adds a lovely flavour to these blondies, but it is optional, so you can omit it if you like. If using, I recommend using a block of white chocolate that you chop yourself. White chocolate chips will work, but they can sometimes make the blondies a bit greasier.
How to make rhubarb blondies
Step 1: Make the rhubarb compote
- Add the rhubarb, sugar and water to a saucepan and bring to a boil. Reduce heat and simmer until jammy in texture.
- Add the reserved rhubarb and cook a few minutes longer, until the rhubarb softens, but still holds shape.
- Add red food colouring to compote, if using.
- Finished compote.
- Transfer compote to a bowl and allow to cool (can be made ahead, covered and refrigerated).
Step 2: Making the rhubarb blondies
- Melt the butter, then whisk the brown sugar into the butter until smooth.
- Add the beaten eggs to the batter.
- Add the vanilla to the batter.
- Add the flour mixture to the batter and stir just until combined.
- Add the chopped white chocolate to the batter (if using).
- Spoon the batter into the prepared 9×9-inch pan and smooth.
- Spoon dollops of the rhubarb compote on top of the batter.
- Use a skewer to swirl the compote into the batter.
- Rhubarb blondies are ready to bake!
Making ahead, storing and freezing
I like to store these blondies in an airtight container either at room temperature for shorter storage or in the fridge for a bit longer storage.
These rhubarb will also freeze well for up to 2 months.
Variations
You can replace some of the rhubarb with some strawberries if you like or if you are short a bit of rhubarb. Simply keep the total weight of the fruit the same.
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Ingredients
Rhubarb Compote:
- 8 oz fresh or frozen rhubarb, chopped into 1/2-inch pieces (about 2 1/4 cups)
- 5 Tablespoons (65 g) white granulated sugar
- 1 1/2 Tablespoons water
- Red food colouring, (optional)
Blondie Batter:
- 3/4 cup (175 g) unsalted butter, melted and slightly cooled
- 1 1/2 cups (275 g) light brown sugar, packed
- 2 large eggs, beaten with a fork
- 1 Tablespoon vanilla extract
- 1 1/2 cups + 2 Tablespoons (200 g) all-purpose flour, spooned and levelled
- 1 teaspoon baking powder
- 1/4 teaspoon Kosher salt, reduce to a pinch if using salted butter
- 3 oz. chopped white chocolate, or about 1/2 cup of white chocolate chips (optional)
Instructions
- Make the Rhubarb Compote: Set aside about 1/2 cup of the rhubarb. Add the remaining rhubarb (about 1 3/4 cups), the white sugar and water in a saucepan. Stir to combine. Bring to a boil over medium heat, then reduce heat and simmer uncovered for 12-15 minutes, or until the mixture is jammy. Add the reserved rhubarb. Stir in and simmer about 2 minutes more or until rhubarb chunks have softened, but still hold their shape. If using, add some red food colouring to the compote and stir in. Remove the compote to a bowl and allow to cool completely at room temperature before using. (If making ahead, cover and refrigerate until needed).
- Preheat oven to 350F. (regular bake setting/not fan assisted). Spray a 9×9-inch square baking pan and line with parchment paper, allowing it to overhang the sides slightly to lift them out later.
- Make the Blondies: (Tip! Be sure not to overheat the butter when melting, or the solids will separate from the fat. Heat until just melted.) Add the melted and slightly cooled butter to a medium bowl. Add the brown sugar and whisk until smooth. *If the mixture is warm at all, allow it to stand for 5 minutes or longer to cool down further, before adding the eggs. If you add eggs to a too-warm mixture, they may cook in the batter! Beat the eggs in a small cup with a fork, then whisk into the butter and brown sugar mixture. Stir in the vanilla.
- In a small bowl, whisk together the flour, baking powder and salt. Add the flour mixture to the batter and using a spatula, stir in just until combined. Stir in white chocolate chips or chunks, if using.
- Add batter to prepared pan and spread evenly into pan. Add about 9 dollops of cooled rhubarb compote randomly on top. Using a skewer, marble the compote into the batter.
- Bake for 35-40 minutes, or until the blondies don't jiggle when the pan is gently shaken.
- Allow to cool completely in the pan, then remove from the pan and cut into squares. *I like to refrigerate for a bit before slicing, for easier and neater cutting.
Notes
More rhubarb recipes to love!
Hi! I’m Jennifer, a home cook schooled by trial and error and almost 40 years of getting dinner on the table! I love to share my favourite recipes, both old and new, together with lots of tips and tricks to hopefully help make your home cooking enjoyable, stress free, rewarding and of course, delicious!
Went to the store to get the ingredients and unfortunately due to no rhubarb had to substitute blue berries. Happy to report they were still super delicious and so easy to make. Got tons of compliments from guests and will definitely be making again. Hope to try with rhubarb as well. Thanks for another great recipe Jennifer!
I’m so glad to hear, Nick :) I feel like this recipe would work well with just about any fruit and good to know that blueberries worked so well. Thanks!
Is this 9×9 or 9×13 pan?
Hi Erin and it’s a 9×9-inch pan (I’ve cleaned that up in the Recipe Card to eliminate any confusion :) Thanks!
Have now made this several times a great favorite with everyone who tastes it.
So glad to hear, Christina! Thanks so much :)
Delicious. The rhubarb season did not last long in Eastern Ontario so I had to supplement some of my own rhubarb with the new sweet strawberries. This made a delicious compote.
I think I put too much compote on the top therefore had to lengthen the cooking time by 5 minutes. This is a case where less is better.
This is an outstanding recipe, thanks Jennifer.
So glad you enjoyed them, Carole Ann and you can’t ever go wrong with the rhubarb and strawberry combination :) Thanks!
These were delicious!! So easy to make and they looked so pretty. My whole family loved them.
So glad to hear, Cathy! Thanks so much :)
These are delicious however, mine were very greasy on the bottom. When cool enough, I slipped the whole thing from the parchment paper to paper towels to soak up the grease. I’m thinking if I make this again, I’d try cutting the butter to 1/2 cup.
Glad you enjoyed them, Debbie. I’ve never had that experience with these blondies (as you can see, mine in the photos are crispy on the bottom, not greasy). You could try reducing the butter, but as I’ve made this recipe many times without that issue, I suspect there is more likely another issue at play. It could be as simple as the brand of butter used, the type of white chocolate used (or using more than specified) or not quite enough flour, for example.