This rhubarb cake has a tender vanilla cake base, lots of tart rhubarb and a streusel topping. The cake itself isn’t overly sweet, which helps balance the rhubarb and keeps the topping from overpowering everything else. It can be made with all-purpose or gluten-free flour.

There’s a generous amount of rhubarb throughout the cake, so you actually taste it in every bite instead of just getting a few scattered pieces here and there.

I assumed that adding fresh or frozen rhubarb to the cake would make it soggy, so I experimented with adding Rhubarb Compote and Rhubarb Preserves. But they actually added too much moisture and made the cake gummy.

slice of rhubarb cake on a white plate with ice cream on the side

So I definitely recommend sticking to fresh or frozen rhubarb! It seems to be difficult to find in the US this year, but hopefully, it’ll start popping up near you soon.

I wanted to post this rhubarb cake as a last-minute dessert for Mother’s Day, but if you can’t find rhubarb in time, it’s still worth bookmarking for later in the season.

If you’re lucky and actually have extra rhubarb to use up, these Rhubarb Bars, Strawberry Rhubarb Crisp and this creamy Rhubarb Fool are great choices.

What’s To Love

Tender texture – the cake stays nice and moist for several days.
Simple ingredients – nothing complicated or hard to find (except the rhubarb in some areas this year!).
Freezer-friendly – freezes well for later.
Works with fresh or frozen rhubarb – no need to wait for perfect produce.

Ingredients

These are just some notes on selected ingredients. Scroll down for the full recipe.

Butter – the butter for the streusel should be cold, while the butter for the cake should be room temperature.
Buttermilk – homemade buttermilk works well here. Just add 1 tablespoon vinegar to a measuring cup and fill to the 1-cup mark with milk.
Rhubarb – cut it into small, even pieces so it bakes evenly into the cake.
Cinnamon – adds a little warmth to the streusel without making the cake taste heavily spiced.

ingredients laid out to make rhubarb cake on a marble table

If you want more ways to use rhubarb, these Rhubarb Preserves and Strawberry Rhubarb Preserves are great for spreading on toast or biscuits. Or if you want something more spoonable, try this Rhubarb Compote.

If you’re wondering if you need the glaze – you definitely don’t! But I have to say that the cake looks incredibly boring without it. And lemon glaze does make it even more irresistible. So it could either be a good or bad thing depending on how much portion control you have. ;)

the baked rhubarb cake in its pan with rhubarb in the background

Fresh vs. Frozen Rhubarb

Fresh rhubarb works best in this cake, but frozen also works with a few small adjustments.

Do not thaw it – add the frozen rhubarb directly to the batter.
Expect a slightly longer bake time – usually about 2-4 extra minutes.
The cake may be slightly more moist – frozen rhubarb releases more liquid as it bakes.
The color can vary – frozen rhubarb often loses its pink color and looks a little more muted after baking. Don’t be surprised if the rhubarb is more of a beige than a pink!

The photographer used fresh rhubarb in the cake in the photos. I just realized that the cake looks a little underbaked towards the bottom, but the cake was fully baked! The area surrounding the rhubarb is just a little moister.

How to Make It

You’ll start by making the streusel topping.

Then mix together the cake batter and fold in the rhubarb.

Spread the batter into a parchment-lined 8×8-inch (20cmx20cm) pan, sprinkle the streusel evenly over the top, and bake until the center tests clean.

collage showing the cake batter, the batter in the pan with streusel on top, the baked cake and the cake with a powdered sugar glaze on top

Tips for Success

Use cold butter for the streusel – otherwise the topping won’t stay crumbly.
Don’t overmix the batter – overmixing can make the cake dense.
Expect a thick batter – that’s normal because of the amount of rhubarb.
Cool completely before slicing – the texture improves quite a bit as it cools.

slice of rhubarb cake on a white plate on a white table with another slice in the background

Troubleshooting

Dense cake – the batter was likely overmixed.
Soggy spots – the rhubarb pieces may have been too large or the cake needed more baking time.
Dry cake – it was probably overbaked.
Streusel melting into the cake – the butter may have gotten too warm. While baking, the streusel may look like it’s melting into the cake, but it will firm up as it finishes baking.

slice of rhubarb cake on a white plate with glaze on top

How to Make Ahead, Store and Freeze

This cake keeps well covered at room temperature for up to 2 days or refrigerated for up to 5 days.

You can also freeze individual slices or the whole cake for up to 3 months. Wrap tightly and thaw overnight in the refrigerator or at room temperature.