Rhubarb Coffee Cake {With Buttermilk + Crumb Topping}

This scrumptious rhubarb coffee cake consists of a moist cake made with buttermilk, a tangy fruit layer in the middle, and a delicious buttery crumb on top. This easy rhubarb cake recipe is perfect for breakfast and brunch, or even as a simple dessert with a scoop of whipped cream!

Rhubarb coffee cake with crumb topping

The homemade rhubarb coffee cake is incredibly tender, soft, and moist, and it’s studded with juicy fruit chunks throughout. The golden-brown, buttery crumbles add the perfect amount of crunchy texture to an otherwise fluffy cake.

My rhubarb crumble cake isn’t overly sweet, making perfect breakfast with a hot cup of coffee or tea, for brunch, as a delicious afternoon snack, or even after dinner when you need a little treat but don’t want to go overboard.

What I also love about this easy rhubarb cake is that it stores beautifully. Simply freeze leftover rhubarb coffee cake and grab a cake snack whenever you feel like it.

And if you love crumble and streusel topping as much as I, be sure to check out our apple crisp bars, blueberry streusel bars, blueberry muffins with streusel, blackberry muffins, apple crumble, and cherry crumble.

Ingredients in rhubarb coffee cake

Aside from the seasonal rhubarb, the ingredients in this easy coffee cake are pretty standard, and you probably have them in your pantry already. The full amounts are in the printable recipe card at the bottom of this post.

• Rhubarb provides this coffee cake recipe with a lovely tartness andcontrasts nicely with the soft, sweet cake and buttery crumb. You need 3 to 4 medium-sized rhubarb stalks. You can use both green and red stalks. But if you want your cake to look like mine with ruby red pieces of fruit in the cake, pick red rhubarb. While I used fresh rhubarb, I’m confident that frozen rhubarb will also work.
• Flour: I used all-purpose flour for both the cake batter and the soft, crumble streusel.
• Sugar: The cake and crumb topping are both made with granulated (white) sugar. You also can prepare the streusel with half granulated sugar and half brown if you like.
• Butter: I opted for salted butter in this rhubarb coffee cake recipe. Making the rhubarb crumble cake with unsalted butter and 1/4 tsp salt is also an option.
• Eggs bind the batter and add richness.
• Buttermilk will make a really delicious rhubarb cake. You could also use sour cream (full fat or reduced) or Greek yogurt, and the coffee cake recipe would still turn out really well.
• Baking powder makes the cake lift and rise. We only add it to the cake batter.
• Vanilla gives a sweet aroma to the cake and balances out the tangy rhubarb.

Optional ingredients

Add the following ingredients if you like to customize your rhubarb coffee cake with crumb topping:

• Cinnamon: Feel free to add 1/2 ground cinnamon to the streusel for that classic coffee cake flavor.
• Almonds: If you like a little crunch in your healthy rhubarb coffee cake, incorporate 1/2 cup chopped or sliced almonds into the crumb mixture.

How to make rhubarb coffee cake

How do you make rhubarb cake from scratch? This no-mixer cake is fast and easy to prepare. Let me walk you through the steps for how to make rhubarb coffee cake with buttermilk and streusel.

Step 1: Prep work

• Position a rack in the center of the oven and preheat to 350°F / 180°C / gas mark 4.
• Generously grease an 8 in x 8 in / 20 cm x 20 cm square baking pan with butter or cooking spray. Line the bottom and sides with parchment (baking) paper; set aside.
• Melt the butter and set aside to cool a little.

Step 2: Prep the rhubarb

• If using fresh, I recommend preparing the rhubarb first. Wash the rhubarb under running water to remove any sand and dirt.
• Pat each stalk with a paper towel until dry. Remove as much liquid as possible, so the excess moisture doesn’t make the cake soggy.
• Chop the rhubarb into 1/4-in / 0.6 cm discs.

Step 3:  Make the streusel

• To make the streusel, stir together the flour and sugar in a medium-sized mixing bowl.
• Drizzle in the melted butter and gently stir with a fork until the ingredients clump together. Leave the mixture lumpy. The larger crumbs give texture to the streusel topping. You can even squeeze handfuls of dough together to form bigger streusel. Add 1 to 2 additional tablespoons of flour if the dough isn’t coming together. Set aside.

Step 4: Mix the coffee cake batter

• Combine the flour, sugar, and baking powder in a large mixing bowl.
• Whisk together the buttermilk, melted butter, eggs, and vanilla extract in a separate mixing bowl or a large measuring cup.
• Pour the wet mixture over the dry. Mix with a spoon or rubber spatula, stirring just until combined, and you see no longer traces of the dry ingredients. The mixture will look lumpy, which is fine. Don’t overmix the batter or try to stir it smooth.

Step 5: Layer the coffee cake

• Spread the cake batter evenly over the prepared cake tin.
• Add the rhubarb discs on top and evenly sprinkle the streusel all over the cake.

Step 6: Bake

• Bake for 50 to 55 minutes, start checking at 45 minutes. The rhubarb coffee cake is done when a toothpick or skewer inserted in the center comes out clean with only a few crumbs but no batter.
• Since all ovens, pans, and fruit vary, your cake may need to bake longer than 55 minutes.
• Cover the cake pan with a piece of aluminum (aluminium) foil if the streusel is browning too much.

Step 7: Cool

• Place the cake pan on a wire rack to cool.
• I recommend allowing the cake to cool for at least 30 minutes before lifting it out of the baking pan (tin).

Step 8: Slice and serve

• Cut the cake into slices and serve at room temperature.
• Optionally, dust the cake with powdered (confectioners’/icing) sugar or drizzle with a simple glaze.

Tips for the best rhubarb cake with buttermilk

The rhubarb coffee cake is really simple, and I’ve rounded up a few tips to give you the best results:

• Don’t over mix the cake batter. Simply stir until everything comes together and no visible clumps of flour remain, and then stop. Overmixing will make the coffee cake dense and tough.
• Check the baking time. You don’t want to over- or underbake the cake.
• Serve with ice cream. A slice of still-warm rhubarb coffee cake with a scoop of fluffy vanilla ice cream tastes heavenly.

Rhubarb crumble cake variations

Rhubarb pairs beautifully with other fruit, particularly strawberry. Blueberries, apples, peaches, and cherries also go well with rhubarb. If you want to change things up, swap half of the rhubarb with any one of these fruits. Let’s look at these ideas:

• Strawberry rhubarb coffee cake: Bake the cake with 1 1/2 cups rhubarb and 1 cup sliced strawberries.
• Lemon rhubarb coffee cake: Add the juice and zest of 1 organic lemon to the cake batter.
• Rhubarb sour cream coffee cake is so good! Simply substitute the buttermilk with the same amount sour cream.
• Blueberry rhubarb coffee cake: For a rhubarb blueberry cake, layer the cake with 1 cup rhubarb and 1 cup fresh or frozen blueberries.
• Rhubarb apple coffee cake: Make the cake with 1 1/2 cups rhubarb and 1 cup chopped apples. And don’t forget to add 1/2 tbsp ground cinnamon to the streusel.

Rhubarb coffee cake muffins

Another idea is to make rhubarb coffee cake muffins. Simply fit a 12-hole muffin pan with paper liners and divide the batter equally between the cups. Add the rhubarb and streusel and bake for 25 to 30 minutes.

FAQ

How much does the recipe yield?

I cut my cake into 16 x 2-in / 5 cm cake bars. You could also slice the cake into 9 x 2.5-in / 6.5 cm squares.

Can I bake this coffee cake recipe in a 9-inch square cake pan instead of an 8-in tin?

Yes! Just note that the cake will be thinner using a 9-inch square pan. You should also check for doneness 5 to 10 minutes earlier than the bake time listed in the recipe.

Can I double the recipe?

Absolutely! As written, the recipe is enough for 1 x 8-by-8-in / 20-by-20-cm baking pan. If you double the ingredients, you’ll have enough to bake this easy rhubarb cake in a 9 in x 13 in / 23 cm x 33 cm cake tin.

Can I use frozen rhubarb?

I made this easy coffee cake with fresh rhubarb and haven’t tested the recipe with frozen. However, I guess that frozen rhubarb will be fine, too.

My suggestion is that you add the rhubarb directly from the freezer and don’t thaw the fruit. You may also need to increase the baking time by a few minutes since the frozen rhubarb will cool the cake batter.

Storing instructions

How to store rhubarb buttermilk coffee cake

Store the entire rhubarb cake recipe at room temperature under a cake dome, or cake pan (tin) turned upside down. Leftover slices are best stored in an airtight food container in the refrigerator.

How long does rhubarb streusel coffee cake last?

The cake will last for 3 days at room temperature or 5 days in the fridge.

Can you freeze rhubarb coffee cake?

Yes, you can freeze the baked rhubarb cake. Once the cake has cooled, wrap the entire cake tightly in plastic wrap/cling film or cut the cake, wrap each bar individually, and place the bars into a large zip-top bag. Freeze for up to 3 months.

How to defrost rhubarb buttermilk cake

When you’re ready to serve, thaw the rhubarb streusel coffee cake at room temperature for 2 to 3 hours. Alternatively, thaw the cake overnight in the refrigerator. Optionally dust with powdered (confectioners’/icing) sugar and serve.