These irresistible rhubarb crumb bars are filled with whole grains, sweetened with natural sugar, and infused with orange zest and juice. Enjoy them from breakfast to dessert!
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I’ve always thought the flavor of rhubarb is in the realm of citrus fruits when it comes to thinking of using it in desserts, but—dare I say—it’s even better, in some ways. It has a fantastic tartness that creates delicious not-too-sweet desserts much like lemon does, but it also has a crunchy heftiness that means you can use it as a filling, like you would berries.
It’s no surprise then that rhubarb does go so well with super-sweet strawberries. There are so many treats I like to make every year that combine the two: puddings, tarts, breads, compotes, even French macarons! Rhubarb and strawberry is one of those classic flavor combos that will never go out of style.
Few desserts put rhubarb front and center though and that’s a shame, in my humble opinion. Rhubarb doesn’t need to hide behind sweeter fruits to shine; it can produce memorable dishes all on its own. Among my favorite rhubarb-only desserts are Rhubarb Panna Cotta and Rhubarb Gelato—two Italian-inspired sweet endings.
But my all-time-winner rhubarb baked treats are these Orange Rhubarb Crumb Bars. Crunchy, slightly chewy, and aromatic with a jammy filling that’s just tart enough to tickle your tastebuds, these rhubarb crumb bars are delightful from breakfast to dessert.
Depending on where you live, rhubarb is in season from late April to June. This is the best time to stock up and freeze extra rhubarb so you can make delicious rhubarb desserts all year long.
To freeze rhubarb, cut off the large leaves at the end of each stalk (these leaves are toxic to humans, so make sure to discard them!). Clean the stalks under cold running water, then chop them into ½ to 1-inch pieces. Pack into freezer bags and keep, frozen, for up to 1 month if stored in a refrigerator freezer, or for up to 12 months if stored in a chest freezer or any other freezer made for long-term storage.
You can make these rhubarb crumb bars with either fresh or frozen rhubarb. When using frozen rhubarb, I like to thaw it in a colander so the excess water drips out. No need to squeeze the rhubarb; once it’s thawed to room temperature, you can simply pat it dry and add it to the recipe as instructed.
In the crumb layers of these rhubarb crumb bars, I like to use wholewheat flour and all-purpose flour at a 50:50 ratio. I like the nuttiness wholewheat flour adds to the flavor of the bars, and I like the extra fiber and nutrients too! In my mind, this combination of wholewheat flour and oats makes it totally okay to enjoy the bars for breakfast and snacks as well as dessert 😉
I like to make these bars with granulated maple sugar because I think maple’s incredible aroma makes the crumb layers even better and sweetens the rhubarb just perfectly. (Learn more about maple sugar.)
If you can’t find maple sugar, you can basically substitute any granulated natural sugar at a 1:1 ratio in these rhubarb crumb bars. Try cane sugar, coconut sugar, turbinado sugar (also called demerara sugar), or even date sugar. Each of these types of sugar will contribute a slightly different flavor to the rhubarb crumb bars, but all of them will create a delicious result. Try a few and pick your favorite!
Orange and rhubarb is another of those classic flavor combinations, and in these rhubarb crumb bars, the orange not only infuses the crumb layers with its deliciously aromatic zest but its juice sweetens the rhubarb, too. For the best flavor, I encourage you to use freshly grated orange zest and freshly squeezed orange juice, but if you don’t have an orange on hand, you can omit the zest and use bottled orange juice instead.
For a change, you could substitute lemon zest for the orange zest at a 1:1 ratio, but decrease the amount of lemon juice to 2 tbsp (30 ml) to make sure the bars won’t be too tart.
The crumb mixture in these rhubarb crumb bars comes together in the food processor in less than a minute. Not only does using a food processor make the process extremely quick and easy, but it also chops up the oats into smaller flakes and incorporates the butter without overworking it, which creates the perfect crunchy crumb.
If you don’t have a food processor, you can make the crumb mixture by hand. Simply incorporate the cold butter using a pastry cutter or a fork, and then mix in the egg with a spatula. The resulting crumb will be chunkier since the oats will remain whole, but the rhubarb crumb bars will be just as delicious.
Make it extra easy to remove these rhubarb crumb bars out of their baking pan by cutting two rectangles of parchment paper the width of your baking pan—one wider and one narrower—and overlapping them, letting extra paper overhangs on all sides of the pan. To unmold the bars, simply pull on this overhanging paper—and voilà! You’re done.
If you don’t want to use two sheets of parchment paper, you can simply use one large rectangle of parchment paper and fit it into the mold, creasing it in the corners and, again, letting extra paper overhang to pull out the bars later.
Isn’t it so disappointing when crumb bars become soft, sometimes even soggy, after they’ve been stored in an airtight container for a day? I’ve got a clever solution for you: refrigerate the bars in an open container instead. Storing these rhubarb crumb bars in the refrigerator keeps them moist (they would dry up quite a bit if they remained at room temperature) and keeping them in an open container prevents the crumbs from absorbing too much moisture from the filling. This is such an easy, perfect remedy to soggy crumb bars! You can keep rhubarb crumb bars refrigerated for up to 1 week.
Rhubarb crumb bars cannot be frozen. The bars would quite simply turn soggy after thawing. Keep extra rhubarb crumb bars in the refrigerator: they will keep for up to 1 week.
You’ll find it in my delicious recipe collection: 25 Rhubarb Dessert Recipes for Spring. Fresh spring rhubarb is a short-lived treat that you absolutely must make the most of! Get inspired by this collection that includes cakes, tarts, crisps, preserves, and many more classic and creative rhubarb-centric dessert recipes.
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