Strawberry Rhubarb Crumb Cake

This strawberry rhubarb cake is made with a crumble topping and loads of fruit filling!

This Strawberry Rhubarb Crumb Cake is actually like a cross between a cake and cobbler.

There’s loads of fruit in the filling, so if you are a strawberry and rhubarb fan, this recipe is perfect for you.

It’s made in three layers: a tender sour cream cake, a fruit filling, and a crumb topping.

The original recipe I tested was nearly perfect, but Reuben wanted there to be more fruit. So that made my life more difficult, but it was worth it to hone this recipe for y’all.

Okay, let’s make it!

If you prefer to learn by watching, make sure to click play on the video above!

Ingredients:

Here’s what you’ll need to make this recipe:

For the Cake:

• Salted Butter: I like to use salted grass-fed butter. Make sure it’s softened, but not so soft that it’s almost melting.
• Sugar: I use organic cane sugar. But feel free to substitute white granulated sugar if that’s what you have.
• Eggs: It’s best if they’re at room temperature, but don’t worry if you forgot to take them out!
• Vanilla Extract: Please use the real deal, pure vanilla extract in this cake. Unless you really love imitation vanilla!
• Lemon Zest: I like the burst of citrus flavor that this lends to this strawberry rhubarb cake.
• Sour Cream: This add a bit of tang and tenderness to the cake layer.
• Flour: I use unbleached organic all-purpose flour, but feel free to substitute your favorite.
• Baking Powder: To add a little lift to the cake!
• Baking Soda: Since we’re using sour cream, the baking soda can react to it.
• Salt: I used Redmond Real Salt, but you could substitute Kosher salt if that’s what you have.

For the Fresh Fruit Filing:

• Rhubarb: I tested this cake with fresh rhubarb, but you might have success with using frozen. 
• Fresh Strawberries: I don’t really recommend using frozen strawberries because you need to chop them. Also, strawberries tend to release quite a bit of liquid when they thaw.
• Sugar: I find that 3/4 cup sugar is just right. It helps to mellow out the tartness of rhubarb, but it doesn’t completely overwhelm it. And then the tart rhubarb balances out the sweetness from the strawberries and the sugar. It’s a symbiotic relationship. 😉
• Flour: Since there’s so much fruit in this cake, I added some flour to thicken up the filling. I experimented with adding lemon juice to the filling, but I think it makes it too wet.

For the Crumble Topping:

• Salted Butter: Again, I like salted, grass-fed butter. 
• Brown Sugar: I use dark brown sugar for a nice rich, caramel flavor.
• Flour: Again, I like to use organic all-purpose flour.
• Salt: I add just a pinch here because I like my topping a bit salty.
• Vanilla Extract: I love the flavor that this adds to the crumble topping!

How to Make Strawberry Rhubarb Cake:

Like I said this cake is made in three parts.

I find it best to make the filling first, then the topping, then the cake. You’ll see why.

Make the Fruit Filling:

Start by making the fruit filling. 

Remove the leaves from your rhubarb. The leaves are toxic, so you DO NOT want to use them.

Cut off a bit of the top part of the stalk as well. The top bit can get a kind of fibrous.

Wash your rhubarb, remove any dirty spots, and finely chop it.

You need the rhubarb to be fairly thinly chopped so it will soften in the oven.

You should have about 4½ cups of chopped rhubarb.

Wash your strawberries and cut off the green tops. 

Chop them fairly finely. 

You’ll get about 4½ cups of chopped strawberries as well.

Place your chopped fruit in a large bowl. 

Add 3/4 cup of sugar and 9 tablespoons (½ cup + 1 tablespoon) of all-purpose flour.

Toss to coat everything evenly and combine rhubarb and strawberries.

Set aside to let the juices release.

Prepare the Baking Pan:

Line a 13×9-inch baking pan with parchment paper.

I like to use this method where you cut slits in the ends of the paper so that it fits in the pan neatly.

Preheat your oven to 350°F.

Make the Crumble Topping:

Now let’s make the crumble topping so it’s ready to go when the cake is done.

Melt ¾ cup (1½ sticks) of salted butter in a medium saucepan over medium heat.

Add ½ cup of dark brown sugar, ¾ tsp of vanilla extract, and a pinch of salt. Stir to combine with the melted butter.

Add 1 ¾ cup + 2 tablespoons of all-purpose flour. 

Stir with a spatula until well mixed and crumbs form.

It will look a bit like large, coarse crumbs.

Set aside for now.

 

Make the Cake:

First, place ¾ cup (1½ sticks) of softened salted butter in the bowl of a stand mixer.

This can also be done with an electric mixer (AKA hand mixer). It just takes a little more patience and arm strength.

Add 1 cup + 2 tablespoons of sugar. 

Beat with the whisk attachment on medium-high speed for 5 minutes, or until light and fluffy, scraping down the sides of the bowl as needed.

Next, add the eggs, one at a time, beating well after each addition, and scraping down the sides as needed.

Add the sour cream, lemon zest, and vanilla extract.

Beat until well combined.

Meanwhile, in a separate bowl, whisk together the dry ingredients in a medium bowl: 1¾ cup all-purpose flour, 1½ teaspoons baking powder, ¾ teaspoon baking soda, and ¾ teaspoon salt.

Add the flour mixture to the batter and beat on low speed just until combined.

It’s okay if the batter is a bit lumpy and there are a few flecks of unmixed flour here and there.

Assemble the Strawberry Rhubarb Cake:

Spread the cake batter into the prepared 13×9-inch cake pan and smooth out the top.

I find that an offset spatula works the best for this.

Dump the strawberry rhubarb fruit mixture on top of the cake and spread it out evenly.

Add the crumb mixture and evenly distribute it with your fingers.

Baking Time and Cooling:

Bake the strawberry rhubarb cake in the preheated oven for 1 hour and 10 minutes. 

IMPORTANT: Make sure to put a baking tray under the cake pan when you bake to catch any spillover!

To check for doneness, shake the pan. If it doesn’t jiggle at all, it’s ready.

Make sure to bake this cake long enough! The fruit filling makes the cake take longer to finish baking.

Cool on a wire rack for at least 45 minutes before cutting and serving.

Serving:

You can serve this cake plain, but you can really take it up a notch if you add a scoop of vanilla ice cream.

A dollop of homemade whipped cream is also delicious.

Storing:

Store any leftovers in an airtight container in the refrigerator for about 3-5 days.

I usually just cover the cake with plastic wrap. Then I lay a piece of aluminum foil on top of that and crimp it down to keep everything airtight.

Bring the cake back to room temperature to serve.

When is Rhubarb in Season?

It really depends on which state you’re in and what variety of rhubarb you grow.

May and June are the best months for rhubarb in Minnesota, but I just harvested some tender stalks from my mother-in-law’s garden in mid-July!

Other states have a longer season for rhubarb. For example, it’s in season from May to October in Illinois. 

You can determine when it’s in season in your state using this handy calculator.

Where to Buy Rhubarb:

Some grocery stores carry rhubarb. Look in the produce section.

You can also sometimes find it at the farmers market.

How to Store Rhubarb:

BTW, here’s a great way to store your rhubarb if you aren’t going to use it right away. Put the rhubarb stalks in a jar with water like a bouquet of flowers! It should keep for at least a day like this.

I harvested this rhubarb in the afternoon, and this is what it looked like the next day.

More Rhubarb Desserts:

• Rhubarb Upside Down Cake
• Rhubarb Crunch
• Sourdough Rhubarb Shortcakes
• Russian Cream with Rhubarb Compote –  one of my favorite recipes for dessert!