Rhubarb Coffee Cake Cobbler is my favorite way to use up a bunch of tart rhubarb when I want something a little more substantial than a crisp. You get a jammy rhubarb layer underneath and a tender vanilla coffee cake on top.
What makes this one stand out for me is the mix of textures: the fruit turns soft and thick, the cake stays fluffy, and the cinnamon streusel adds a little crunch. It’s sweet, but the rhubarb keeps it sharp in a good way, especially with a little lemon in the filling.
I like serving this as a simple weekend dessert, but it also works as a brunch bake if you’re into “dessert for breakfast.” It’s especially good with plain coffee or tea, and I usually scoop it while it’s still a bit warm.
Why You’ll Love This Recipe
Two desserts in one: It eats like a cobbler, but the topping is a true coffee cake with that soft, sliceable texture.
Tart-sweet flavor: Rhubarb brings the tang, and the vanilla-lemon combo keeps the filling tasting bright instead of flat.
That streusel top: The cinnamon crumb layer gives you a little crunch and makes the whole pan look finished without extra effort.
Easy to share: A 9-inch square pan slices neatly into servings, so it’s great for potlucks and casual get-togethers.
Flexible ingredients: Frozen rhubarb works, and you’ve got simple swaps if you don’t have buttermilk on hand.
Ingredients You’ll Need
Rhubarb filling
- Rhubarb: Fresh rhubarb is great, but frozen works too (no need to thaw). I just slice it into fairly even pieces so it cooks down at the same rate.
- Granulated sugar: This sweetens the filling and takes the edge off the rhubarb. If your rhubarb is extra tart, I wouldn’t cut the sugar too much.
- Cornstarch: This is what thickens the fruit juices into a scoopable filling instead of a runny puddle.
- Lemon juice: A little lemon keeps the flavor sharp and bright. Bottled is fine if that’s what you have.
- Vanilla extract: Vanilla softens the tartness and makes the filling taste more like a dessert, not just stewed fruit.
- Salt: Just enough to keep the sweetness in check.
- Unsalted butter: Dotting butter over the filling helps it cook up a little richer and smoother.
Coffee cake topping
- All-purpose flour: I use regular flour here. Spoon and level it if you tend to pack flour into the cup.
- Baking powder: This gives the topping most of its lift, so make sure yours is fresh.
- Baking soda: A small amount helps the buttermilk do its job and keeps the crumb tender.
- Salt: Don’t skip it. It keeps the cake from tasting flat.
- Granulated sugar: Sweetens the cake layer and helps it brown nicely on top.
- Egg: One egg is enough to bind the batter and give it structure so it spreads well over the fruit.
- Buttermilk: This is what makes the cake topping taste like coffee cake. Sour cream or plain Greek yogurt thinned with a splash of milk works too.
- Vanilla extract: Makes the topping taste warm and bakery-ish in the best way.
- Unsalted butter: Melted butter keeps this easy and gives the topping a richer crumb.
Streusel
- Light brown sugar: Brown sugar is the classic streusel flavor. Dark brown sugar works too if that’s what you’ve got.
- All-purpose flour: This gives the streusel its crumbly structure so it doesn’t just melt into the cake.
- Ground cinnamon: Cinnamon with rhubarb is always a good idea, and it makes the whole pan smell amazing while it bakes.
- Unsalted butter: Softened butter is easiest for getting those nice clumps. If it’s too warm, the streusel can turn pasty.
- Pecans (optional): I like the crunch, but you can leave them out or swap in walnuts.
Recipe Instructions
- Preheat the oven: Heat the oven to 350°F. Grease a 9-inch square baking dish.
- Mix the filling: In a bowl, mix the rhubarb, sugar, cornstarch, lemon juice, vanilla, and salt. Spread it evenly in the baking dish, then dot the top with the butter.
- Mix the dry ingredients: Whisk the flour, baking powder, baking soda, and salt together in a medium bowl.
- Mix the wet ingredients: In another bowl, whisk the sugar, egg, buttermilk, vanilla, and melted (cooled) butter until combined.
- Make the batter: Pour the wet mixture into the dry ingredients and stir just until you don’t see dry flour. Don’t overmix.
- Add the topping: Dollop the batter over the rhubarb, then gently spread it out so it mostly covers the filling.
- Make the streusel: Mix the brown sugar, flour, cinnamon, and softened butter until crumbly. Stir in the pecans if you’re using them.
- Bake: Sprinkle the streusel over the batter. Bake for 40 to 50 minutes, until the topping is golden and a toothpick inserted into the cake portion comes out clean.
- Cool: Let it cool for about 15 minutes before serving so the filling can thicken up.
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
Slice the rhubarb pretty evenly. If you have a mix of tiny pieces and big chunks, the small ones can turn to mush before the bigger pieces soften.
Don’t overmix the cake batter. Stir just until the flour disappears. Overmixing makes the topping bake up tougher and less tender.
Spread the batter gently. It’s a thick batter, and it’s easy to drag rhubarb into the topping if you press too hard. I do small dollops all over, then connect them with a light hand.
Watch the center for doneness. The edges brown first, so check the middle with a toothpick in the cake part (not down in the fruit). If the top is browning fast, you can loosely lay foil over it near the end.
Let it sit before scooping. Even 15 minutes helps the filling set up so you get more cobbler and less juice running across the plate.
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
- Vanilla ice cream: A scoop on the side is classic with warm cobbler. I like how it melts into the cinnamon streusel.
- Whipped cream: Soft whipped cream (even the lightly sweetened kind) is really nice here. It keeps the focus on the rhubarb.
- Strawberries: If you have fresh strawberries, slice a few and serve them alongside. Strawberry and rhubarb together just makes sense.
- Coffee or tea: This is great with plain coffee, especially if you’re serving it for brunch. Black tea works well too.
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 leftovers covered in the fridge for up to 4 days. The topping softens a little in the fridge, but the flavor stays great.
To warm it up, reheat individual servings in the microwave, or warm the whole dish in a 300°F oven until heated through. If you’re using the oven, cover loosely with foil if the top is already browned.
You can also freeze individual portions or freeze the whole baked dish once it’s fully cooled. Thaw in the fridge overnight before reheating.
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 frozen rhubarb?
Yes. Use it straight from frozen (don’t thaw), spread it in the dish, and bake as directed. I usually add about 5 minutes to the baking time since the filling starts colder.
What can I use instead of buttermilk?
Sour cream or plain Greek yogurt works well here. I thin it with a splash of milk so it’s closer to buttermilk, then measure and use it the same way.
How do I know the coffee cake topping is baked through?
The top should be golden, and a toothpick inserted into the cake portion should come out clean. Try to avoid poking all the way down into the fruit, since the filling will be juicy even when it’s done.
Can I make it less sweet?
Yes. I’ve done this with less sugar and it still works: use 1/2 cup sugar in the filling and 1/3 cup sugar in the topping. The rhubarb will taste more tart, which some people prefer.
Do I have to use pecans in the streusel?
No, you can leave them out. The streusel is still crunchy and good without nuts, or you can swap in walnuts if that’s what you keep around.
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 Cobbler
INGREDIENTS
Rhubarb filling
- 4 cups rhubarb sliced
- 3/4 cup granulated sugar
- 2 tbsp cornstarch
- 1 tbsp lemon juice
- 1 tsp vanilla extract
- 1/4 tsp salt
- 2 tbsp unsalted butter.
Coffee cake topping
- 1 1/2 cups all purpose flour
- 2 tsp baking powder
- 1/4 tsp baking soda
- 1/2 tsp salt
- 1/2 cup granulated sugar
- 1 large egg
- 1 cup buttermilk
- 1 tsp vanilla extract
- 6 tbsp unsalted butter melted and cooled.
Streusel
- 1/2 cup light brown sugar packed
- 1/2 cup all purpose flour
- 1 tsp ground cinnamon
- 4 tbsp unsalted butter softened
- 1/4 cup chopped pecans optional.
INSTRUCTIONS
Prep and assemble
- heat oven to 350 F and grease a 9 inch square baking dish
- mix rhubarb sugar cornstarch lemon juice vanilla and salt then spread in dish and dot with butter
- whisk flour baking powder baking soda and salt
- whisk sugar egg buttermilk vanilla and melted butter then stir into dry ingredients just until combined
- dollop batter evenly over rhubarb and gently spread to mostly cover.
Add streusel and bake
- mix brown sugar flour cinnamon and butter until crumbly then stir in pecans if using and sprinkle over batter
- bake until topping is golden and a toothpick in the cake portion comes out clean 40 to 50 minutes
- cool 15 minutes before serving to let filling thicken.
