Learn how to make this easy rhubarb blueberry coffee cake with streusel topping. This blueberry rhubarb coffee cake may be enjoyed for breakfast or as a dessert with any other meal. It would also make a wonderful addition to any blueberry-themed gathering. Part crumb cake recipe, part traditional coffee cake recipe, it’s a great treat. With the fruit filling, it’s also a fabulous way to use fresh or frozen garden produce. Need more streusel topping? This recipe has an extra thick layer. If you’re trying to decide whether to make a crumb cake vs. coffee cake, this recipe is a combination of both. Read on for the best rhubarb blueberry (or blubarb, great word) streusel coffee cake you will ever make!
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The Versatile Rhubarb Blueberry Combination
Both rhubarb and blueberries grow well in our garden. This has led to the creation of many rhubarb recipes. Some of the most popular are easy rhubarb jam (with some unexpected ingredients), tangy rhubarb orange jam, and other rhubarb blueberry combinations like blueberry rhubarb crisp (aka blubarb crisp), and home-canned blueberry syrup. If you have a surplus of either rhubarb or blueberries, these recipes might be just what you’re looking for.
Supplies for Rhubarb Blueberry Coffee Cake
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Basic kitchen supplies are all you need for this recipe, including a large skillet and a square 8 by 8 by 2 or 9 by 9 by 2 baking pan. A stand mixer is nice, but not a requirement. I like to use my late mother-in-law’s Kitchenaid mixer, which saves me a lot of time. It’s one of my favorite kitchen appliances. Even though the awesome retro gold color I have is not available, the mixer may be found in many other colors. Mine is one that has the bowl lift, like this one, and is capable of handling even the heaviest mixing tasks.
Ingredients for Rhubarb Blueberry Coffee Cake
Fruit Filling:
3/4 cup fresh or frozen rhubarb, cut into chunks
3/4 cup fresh or frozen blueberries
1/4 cup water
1/4 cup sugar
2 tablespoons cornstarch
Coffee cake batter:
1 1/2 cups all-purpose flour
1/2 cup sugar
1/2 teaspoon baking powder
1/4 teaspoon baking soda
4 tablespoons butter
1 beaten egg
1/2 cup milk
1 1/2 teaspoons lemon juice
1/2 teaspoon vanilla
Streusel topping:
4 tablespoons brown sugar
2 tablespoons flour
2 teaspoons ground cinnamon
2 tablespoons butter
Directions for Rhubarb Blueberry Coffee Cake
Grease a square 8 by 8 by 2 or 9 by 9 by 2 baking pan and set aside. (I like to use a wrapper from a stick of butter to spread around a bit of shortening to do this.) Preheat the oven to 350 degrees.
To make the sour milk (the same as buttermilk substitute, one of my favorite kitchen shortcuts) combine 1/2 cup of milk with 1 and 1/2 teaspoons lemon juice and set aside. I like to just mix it in a glass measuring cup.
In a saucepan combine the chopped rhubarb and the blueberries along with the water. Bring the mixture to boiling over medium to medium-high heat, then reduce the heat to low. Cover and simmer about 5 minutes or until the rhubarb is tender. Combine 1/4 cup of the sugar and the cornstarch. Stir that into the fruit mixture, then cook and stir until thickened and bubbly. Stir and cook for 2 more minutes, then set aside.
In a mixing bowl (or a mixing bowl of a stand mixer) stir together 1/2 cup of sugar, the 1 and 1/2 cups flour, the baking powder and baking soda. Cut in 4 tablespoons butter (I always use real butter) until the mixture looks like fine crumbs. In the measuring cup that contains the sour milk, add the egg and vanilla. Beat to combine, then add the sour milk mixture to the flour mixture. Mix just until moistened.
Spread half of the batter in your greased square baking pan. Spread the fruit mixture over the batter.
Drop the remaining batter in small mounds on top of the filling and spread to cover the filling.
For the streusel topping, combine the brown sugar, 2 tablespoons of flour, and 2 teaspoons ground cinnamon. With a fork or pastry blender, cut in 2 tablespoons of butter until the mixture is crumbly. Sprinkle over batter.
Bake in the oven for 40 to 45 minutes or until golden brown on top. Serve warm with a large dollop of butter on top. This recipe makes 9 servings.
Rhubarb Blueberry Coffee Cake
Equipment
- 1 square 8 by 8 by 2 or 9 by 9 by 2 baking pan
- 1 large skillet
- 1 stand mixer optional
Ingredients
- ¾ cup fresh or frozen rhubarb, cut into chunks
- ¾ cup fresh or frozen blueberries
- ¼ cup water
- ¼ cup sugar
- 2 tablespoons cornstarch
Coffee Cake Batter
- 1½ cups all-purpose flour
- ½ cup sugar
- ½ teaspoon baking powder
- ¼ teaspoon baking soda
- 4 tablespoons butter
- 1 beaten egg
- ½ cup milk
- 1½ teaspoons lemon juice
- ½ teaspoon vanilla
Streusel Topping
- 4 tablespoons brown sugar
- 2 tablespoons flour
- 2 teaspoons ground cinnamon
- 2 tablespoons butter
Instructions
- Grease a square 8 by 8 by 2 or 9 by 9 by 2 baking pan and set aside.
- Preheat the oven to 350 degrees.
- To make the sour milk, combine 1/2 cup of milk with 1 and 1/2 teaspoons lemon juice and set aside.
- In a saucepan combine the chopped rhubarb and the blueberries along with the water. Bring the mixture to boiling over medium to medium-high heat, then reduce the heat to low.
- Cover and simmer about 5 minutes or until the rhubarb is tender.
- Combine 1/4 cup of the sugar and the cornstarch. Stir that into the fruit mixture, then cook and stir until thickened and bubbly.
- Stir and cook for 2 more minutes, then set aside.
- In a mixing bowl (or a mixing bowl of a stand mixer) stir together 1/2 cup of sugar, the 1 and 1/2 cups flour, the baking powder and baking soda.
- Cut in 4 tablespoons butter until the mixture looks like fine crumbs.
- In the measuring cup that contains the sour milk, add the egg and vanilla. Beat to combine, then add the sour milk mixture to the flour mixture. Mix just until moistened.
- Spread half of the batter in your greased square baking pan.
- Spread the fruit mixture over the batter.
- Drop the remaining batter in small mounds on top of the filling and spread to cover the filling.
- For the streusel topping, combine the brown sugar, 2 tablespoons of flour, and 2 teaspoons ground cinnamon.
- With a fork or pastry blender, cut in 2 tablespoons of butter until the mixture is crumbly. Sprinkle over batter.
- Bake in the oven for 40 to 45 minutes or until golden brown on top.
- Serve warm with a large dollop of butter on top.
What to Serve with Rhubarb Blueberry Coffee Cake
This blueberry rhubarb coffee cake is always excellent when topped with a generous dollop of real butter. That’s the way our favorite coffee cake is served at Carolyn’s Cafe in Redlands, California. Some may prefer to call this a blueberry rhubarb crumble and serve it topped with ice cream. Some people may even call this a Rhubarb blueberry buckle coffee cake. Whatever you name it, this rhubarb blueberry treat is delicious any time of the day. For a delicious beverage option, you could serve the coffee cake with hot mulled cider (wassail).
Common Rhubarb Questions
Do you have to peel rhubarb? No, it is not necessary to peel rhubarb. When it is cooked, the rhubarb stalk becomes soft. Save time and skip the peeling!
When is the best time to harvest rhubarb? Rhubarb from an established plant is best harvested in early summer. Although you can harvest rhubarb throughout the summer, it may weaken the crop for the next year.
Is rhubarb toxic before cooking? The rhubarb stalk is not toxic, and you could munch on it raw. However, it is very sour. Cooking and sweetening it makes it much more tasty.
Other Blueberry Recipes
If you love using blueberries in recipes, I have got some ideas for you. You might like to whip up a batch of easy blueberry lemon scones or a blueberry cobbler. Stock you pantry shelves with canned blueberry lime jam, blueberry raspberry jam, or blueberry syrup.
More Food Inspiration
Thinking of working this rhubarb blueberry coffee cake recipe into your recipe rotation? It’s always nice to have a plan when it comes to meals. If you’re looking for a way to get more organized with your meal planning efforts, I’ve got something for you. Free, editable meal planners! The templates can be used over and over, as often as you need them. You can make as many duplicates as you like, and you’ll be able to save old meal plans for future reference. I hope it simplifies things for you.
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I hope you enjoy making rhubarb blueberry coffee cake. May all of your baking endeavors meet with great success!
Lisa Mitchell is a wife, mom, and school librarian who likes to create and share recipes, often using fresh ingredients from her family’s small Pacific Northwest farm. To learn more about what this website has to offer, click on over to the Welcome page.
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Last week I went to inspect the allotment. Because March this year was unexpectedly warm, the rhubarb was already grown, so I picked a few stems that are still in the fridge, waiting for a good recipe. Thanks, Lisa! I will make yours:)
Oh, awesome! I’d love to know how your version of the rhubarb blueberry coffee cake turns out!
Though I am not the biggest fan of rhubarb, I know for a fact that my husband would love this rhubarb blueberry coffee cake, so I will have to give this one a try. He’ll never turn down me trying a new recipe with a delicious dessert.
That’s one of the best things about families. They are always happy to try dessert experiments!
Thanks for sharing this delicious rhubarb blueberry coffee cake recipe! I love blueberry and rhubarb and it’s wonderful that they are used both in this recipe. And I learned something more about rhubarb. 🙂
Oh, I’m so glad. I hope this rhubarb blueberry coffee cake recipe will bring pleasure to your taste buds!
I love any and all rhubarb blueberry recipes. Thank you for sharing this coffee cake recipe. I’m always looking for more ways to use rhubarb and blueberries together.
It really is a great combination. I’m happy to be able to add to your collection of rhubarb blueberry recipes.