Rhubarb Coffee Cake is the kind of bake I reach for when I want something tender, a little tart, and actually satisfying with a mug of coffee. The sour cream batter stays soft for days, and the rhubarb keeps it from tasting flat or too sweet.
My favorite thing here is the contrast between the buttery cinnamon streusel and the bright rhubarb layer. It’s a simple, classic coffee cake texture, but the rhubarb bite makes it feel more interesting than the usual crumb cake.
I make this most often for weekend breakfasts, casual brunch, or an easy dessert when I don’t want frosting. It’s especially nice served slightly warm with a thin vanilla glaze, but it’s also good plain.
Why You’ll Love This Recipe
Soft crumb: Sour cream makes the cake stay tender, not dry or bready, even on day two.
That tart rhubarb: Rhubarb brings a sharp little pop that keeps the whole pan from tasting overly sweet.
Big streusel energy: The cinnamon crumb topping bakes up buttery and crisp, which is exactly what I want on coffee cake.
9×13 friendly: It’s an easy pan for slicing into clean squares, and it’s great for sharing.
Optional glaze: You can keep it simple, or add a quick drizzle for a sweeter finish without committing to frosting.
Ingredients You’ll Need
Cake Batter
- All-purpose flour: I use regular flour here. It gives the cake enough structure so it slices neatly.
- Baking powder: Helps the batter lift a little so the cake doesn’t bake up heavy.
- Baking soda: Works with the sour cream to give you a tender crumb.
- Fine salt: Don’t skip it. It keeps the cake and streusel from tasting one-note.
- Unsalted butter: Softened butter creams best with sugar, so you get a lighter texture.
- Granulated sugar: Keeps the cake classic and clean-tasting, especially with tart rhubarb.
- Eggs: Bring the batter together and help it set up into a sliceable cake.
- Vanilla extract: A steady background flavor that makes the sour cream batter taste more like “coffee cake.”
- Sour cream: This is the whole point for me. It makes the cake moist and gives it that bakery-style tenderness (Greek yogurt works too).
Rhubarb Layer
- Rhubarb: Fresh is great, but frozen works fine too—just thaw and drain it well so it doesn’t waterlog the middle.
- Granulated sugar: Takes the edge off the rhubarb so it bakes up pleasantly tart instead of sharp.
- All-purpose flour: A little flour helps catch the juices so you don’t end up with a soggy stripe.
Streusel Topping
- Light brown sugar: I like light brown sugar here because it stays buttery and caramel-y without getting too dark.
- All-purpose flour: This is what turns the melted butter into crumbles instead of a slick topping.
- Ground cinnamon: Classic coffee cake flavor. If you like a stronger spice note, you can bump it up a bit.
- Fine salt: Keeps the streusel from tasting overly sweet and helps the butter flavor come through.
- Unsalted butter: Melted butter makes an easy streusel—no pastry cutter needed.
- Pecans (optional): I add them when I want a little crunch. You can leave them out for a more classic crumb topping.
Vanilla Glaze (Optional)
- Powdered sugar: Makes a smooth, quick drizzle that sets up nicely on top.
- Milk: Start with a little and add more only if you need it thinner.
- Vanilla extract: Keeps the glaze from tasting like plain sugar.
- Salt: Just a pinch makes the glaze taste less flat.
Recipe Instructions
- Preheat the oven: Heat the oven to 350°F. Grease a 9×13-inch baking pan, or line it with parchment.
- Mix the dry ingredients: Whisk the flour, baking powder, baking soda, and salt together in a medium bowl, then set aside.
- Prep the rhubarb: Toss the diced rhubarb with granulated sugar and flour. Set it aside while you make the batter.
- Make the streusel: Stir the brown sugar, flour, cinnamon, and salt together, then mix in the melted butter until crumbly. Stir in pecans if you’re using them.
- Cream the butter and sugar: Beat the softened butter and granulated sugar until light and fluffy.
- Add the eggs and vanilla: Beat in the eggs one at a time, then mix in the vanilla.
- Add the dry ingredients and sour cream: Mix in half the dry ingredients, then the sour cream, then the remaining dry ingredients. Stop mixing as soon as you don’t see dry flour.
- Spread the batter: Spread half of the batter in the prepared pan.
- Add the rhubarb: Sprinkle the rhubarb evenly over the batter.
- Add the remaining batter: Dollop the rest of the batter over the rhubarb, then gently spread it out to cover.
- Add the streusel: Scatter the streusel evenly over the top.
- Bake: Bake for 45 to 55 minutes, until the center springs back and a toothpick comes out with moist crumbs.
- Cool: Cool in the pan for about 20 minutes, then slice.
- Glaze (optional): Whisk the powdered sugar, milk, vanilla, and a pinch of salt. Drizzle over slightly warm or fully cooled cake.
Some of my tips!
This is the part that really makes a difference. If you only read one section, make it this one because this is where I share the little trick that helps the recipe turn out so well.
Recipe Tips & Tricks
Drain frozen rhubarb well. If you’re using frozen, thaw it completely and drain off the liquid. Extra moisture can make the middle sink or feel a little gummy.
Stop mixing when the flour disappears. Once the last bit of dry flour is gone, quit. Overmixing makes coffee cake tougher than it needs to be.
Use a light hand when spreading the top layer. The rhubarb underneath can make the batter want to drag. Dollops first, then spread gently.
Tent with foil if the topping darkens fast. Some ovens brown streusel quickly. A loose foil tent for the last 10 to 15 minutes keeps it from getting too dark.
Add a little extra flavor if you want. I like a bit of orange zest in the batter, or a pinch of ground ginger with the rhubarb. Both work nicely with the tart fruit.
Make some touches!
There are plenty of easy ways to serve this depending on the occasion. Keep it simple, or add a few small touches to make it feel a little more special.
Serving Suggestions
- Coffee or espresso: This is a true coffee cake situation. I like it with black coffee or a latte.
- Whipped cream: A small spoonful on the side is nice if you’re serving it as dessert. It also looks a little more finished on a plate.
- Fresh berries: Strawberries or raspberries are good with the rhubarb, especially if you want something fresh next to the cake.
- Vanilla ice cream: If you warm a square for a few seconds, ice cream melts right into the streusel. It’s simple and really good.
Save it for later
This section covers how to store leftovers and what parts of the recipe you can prepare ahead of time.
Storage and Make Ahead
Store leftover cake covered at room temperature for 2 days, or move it to the fridge if your kitchen runs warm. I usually keep it right in the pan, tightly covered.
Refrigerate for up to 4 days if you want it to last longer. The crumb stays soft, but the streusel will lose a little crispness in the fridge.
For serving, I like to warm individual squares for a few seconds in the microwave. If you want the streusel crisper, warm slices in a low oven instead.
You can freeze individual portions or freeze larger slabs wrapped well. Thaw in the fridge overnight, then bring to room temp or warm briefly before serving.
A few quick answers
This section covers a few extra details that may help before you head to the recipe card.
Recipe FAQs
Can I use Greek yogurt instead of sour cream?
Yes. Full-fat Greek yogurt is the closest swap and bakes up very similar. I’d avoid fat-free because the cake can turn out a bit drier.
Can I use frozen rhubarb?
You can. Thaw it first and drain it really well, then toss it with the sugar and flour like the recipe says.
How do I know when the coffee cake is done?
The center should spring back when you press it lightly, and a toothpick should come out with moist crumbs (not wet batter). If the toothpick is clean, it may be slightly overbaked.
What if my streusel is browning too much?
Loosely tent the pan with foil for the last 10 to 15 minutes. The cake will finish baking through, and the topping won’t get too dark.
You might also like
Before you go, take a look at a few other recipes below the recipe card. They use similar ingredients in a different way and are worth saving too.
MORE DINNER RECIPES TO TRY
Rhubarb Coffee Cake
INGREDIENTS
Cake Batter
- 2 cups all purpose flour
- 1 tsp baking powder
- 1 tsp baking soda
- ½ tsp fine salt
- ¾ cup unsalted butter softened
- 1 cup granulated sugar
- 2 large eggs
- 2 tsp vanilla extract
- 1 cup sour cream.
Rhubarb Layer
- 2 cups rhubarb diced
- 2 tbsp granulated sugar
- 1 tbsp all purpose flour.
Streusel Topping
- ¾ cup light brown sugar packed
- ¾ cup all purpose flour
- 1 tsp ground cinnamon
- ¼ tsp fine salt
- 6 tbsp unsalted butter melted
- ½ cup chopped pecans optional.
Vanilla Glaze Optional
- ¾ cup powdered sugar
- 1 tbsp milk
- ½ tsp vanilla extract
- pinch of salt.
INSTRUCTIONS
Prep
- heat oven to 350 F
- grease a 9x13 inch baking pan or line with parchment
- whisk flour baking powder baking soda and salt in a bowl
- toss rhubarb with sugar and 1 tbsp flour and set aside
- mix streusel ingredients until crumbly and set aside.
Batter And Assembly
- cream butter and granulated sugar until light and fluffy
- beat in eggs one at a time then vanilla
- mix in half the dry ingredients then sour cream then remaining dry ingredients just until combined
- spread half the batter in the pan
- sprinkle rhubarb evenly over batter
- dollop and spread remaining batter over rhubarb
- scatter streusel evenly over the top.
Bake And Finish
- bake until the center springs back and a toothpick comes out with moist crumbs 45 to 55 minutes
- cool in pan 20 minutes then slice
- if using glaze whisk powdered sugar milk vanilla and salt then drizzle over slightly warm or fully cooled cake.
