This easy rhubarb streusel cake is the perfect balance of tart and sweet, making it the best spring and summer bake. The moist vanilla cake has fresh rhubarb mixed into the batter, and it's sprinkled with a buttery sugar streusel that melts in as it bakes. Dusted with powdered sugar, it's a bakery-style cake that's great to serve for guests, or a simple homemade treat!
Tart rhubarb is perfectly balanced with white sugar in the cake and dusted with powdered sugar on top after baking.
This is my first rhubarb recipe on the blog and I couldn't be more excited to leap into all the fun spring bakes!
Rhubarb is a super popular veggie to bake with in Poland, and this Rhubarb Cake (Ciasto Rabarbarowe) is a classic in our house!
The contrast between the tangy rhubarb and the crumbly topping is what makes this cake so irresistible. Let's get to baking!
Step by step instructions
Here is how to make and bake this easy Rhubarb Streusel Cake. You will need an 8×8 square pan lined with parchment paper, an electric handheld mixer, three mixing bowls, and a spatula.
Step 1 - Make streusel. In a medium-sized bowl, add softened butter, sugar, and flour. Mix until a crumb forms. Set in the fridge to chill.
Step 2 - Mix dry ingredients. In a medium-sized bowl, add in the flour, baking powder, cornstarch, and salt. Mix together and set aside.
Step 3 - Cream butter and sugar. In a mixing bowl, add the softened butter and white sugar. Cream for 3-4 minutes on medium speed until pale in colour and fluffy.
Step 4 - Add eggs. Place in the eggs and continue mixing on medium speed for 2-3 minutes.
Step 5 - Add in sour cream and vanilla. Add in the sour cream and vanilla and combine with a spatula until smooth.
Step 6 - Add in dry ingredients. Mix in the dry ingredients using a spatula until just combined. Don't over-mix!
Step 7 - Spread in pan. Add the batter into the prepared pan and spread out evenly.
Step 8 - Add rhubarb. Chop the rhubarb into small pieces and place on top of the batter. Then sprinkle the streusel on top.
Step 9 - Bake. Bake the cake for 45-55 minutes or until a toothpick inserted comes out dry or with a few crumbs on it.
Allow to cool, dust with powdered sugar, slice, and enjoy!
FAQ
What is rhubarb?
Rhubarb is a vegetable grown in early spring and all summer. It comes in red and green colours, and has a sour taste to it. Once it's baked with sugar, it has a sweet and sour taste.
Why is my rhubarb green?
There are a lot of different varieties of rhubarb. Some grow more red, and some grow more green! They are all very similar in flavour (sour/tangy) when consumed raw.
When is rhubarb season?
Rhubarb season is typically late April through June. It is one of the first veggies to grow during the spring. When shopping for rhubarb at your local grocery store, look for crisp firm rhubarb that are blemish free.
Storing
Rhubarb cake is best eaten day of or the next day. It can stay in the refrigerator for up to 5 days in an airtight container.
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Easy Rhubarb Streusel Cake
Ingredients
For the streusel
- 3/4 cup all-purpose flour
- 5 tbsp unsalted butter softened
- 1/3 cup white sugar
For the cake
- 1 cup all-purpose flour
- 1 1/4 tsp baking powder
- 1 tbsp cornstarch
- 1/4 tsp salt
- 1/2 cup unsalted butter room temperature
- 1/2 cup white sugar
- 2 eggs room temperature
- 1 tbsp vanilla extract
- 1/3 cup sour cream room temperature
- 1 1/4 cups rhubarb cut into small pieces
Instructions
- Preheat oven to 350℉/176℃. Line an 8x8 pan with parchment paper and set aside.
- In a medium-sized bowl, mix together the flour, cornstarch, baking powder, and salt. Set aside.1 cup all-purpose flour, 1 1/4 tsp baking powder, 1/4 tsp salt, 1 tbsp cornstarch
Make the streusel
- In another medium-sized bowl, add softened butter, flour, and sugar. Mix together until crumbs form. Set aside.3/4 cup all-purpose flour, 5 tbsp unsalted butter, 1/3 cup white sugar
Make the cake
- In a large mixing bowl, add softened butter and white sugar. Using an electric mixer, mix for 3-4 minutes until light and fluffy. Scrap the sides of the bowl as needed.1/2 cup unsalted butter, 1/2 cup white sugar
- Add in eggs and continue mixing for 2-3 minutes.2 eggs
- Add in vanilla and sour cream. Mix together using a spatula.1 tbsp vanilla extract, 1/3 cup sour cream
- Add in the dry ingredients and gently mix until a soft batter forms. Do not over-mix!
- Spread evenly into the prepared pan.
- Chop the rhubarb into small pieces. Sprinkle on top of the cake .1 1/4 cups rhubarb
- Sprinkle streusel evenly on top.
- Bake the cake for 45-55 minutes. It will be ready when a toothpick inserted comes out dry or with a few crumbs. If there is still wet batter, it is not done baking.
- Allow to cool, dust with powdered sugar, slice, and enjoy!
Jupiter & Maud says
These look so yummy! Thank you for sharing!
Ania says
Thank you so much Jupiter & Maud! It is such a great cake for the season 😊
Cat says
We made this and it was really good. We're not experienced bakers and often our attempts don't meet our hopes/expectations. But this one did! We'll be making it again!
Ania says
Hi Cat! I'm so so glad to hear the cake turned out delicious. I always try to make my recipes as simple to follow as possible and I'm really happy to hear that this attempt met your sweet treat expectations 🙂 Thanks for sharing, and enjoy the cake!