A lovely, buttery brown sugar cake, this Rhubarb Crumble Cake features is filled with rhubarb and has a unique crumble topping.
I know there are a ton of rhubarb cakes on the Internet, but I wanted to add just one more to the mix for a couple of reasons.
First, this was a lovely cake and a great way to use your Spring rhubarb, but it is also a great way to enjoy all the Summer fruit, simply by changing up the fruit. This cake is versatile.
Secondly, this cake has a really unique crumble topping and one that I think any baker would love to "discover" (if you haven't already), because it's one of those baking things that you can tuck away and use on other cakes or coffee cakes.
So let's take these one at a time!
Make this cake with all the Summer fruit!
While I made this as a rhubarb cake (remember that bumper crop of rhubarb I"m dealing with), this cake would be equally nice with blueberries, raspberries, blackberries, peaches, apples and more.
The cake itself is what I would call almost a pound cake. Not quite as dense, lightly sweet and lovely and buttery. It's a great base cake for rhubarb and just about any fruit, for that matter.
Steal this crumble topping idea and use it on other cakes!
So I mentioned the unique crumble topping above and what makes it unique is that it's not what you might expect by looking it. It's not a brown sugar/butter topping. It's made from a small amount of the cake batter, that gets mixed up with some cinnamon and some more flour, forming into a crumble mixture.
As such, it delivers the crunchy, crumble, without adding a layer of butter and sugar on top. Not that there's anything wrong with that, it's just that sometimes it's nice to enjoy a cake that's not all that.
That's also why there is a sprinkling of sugar on top (and you thought it was just sugar on sugar :)
Ingredient Notes for Rhubarb Crumble Cake
Rhubarb: You'll notice the rhubarb I've used here is quite green. I have one rhubarb plant that is just really green, even when mature and ready to pick. Sure, the ruby red rhubarb is pretty, but that is usually the greenhouse, forced variety. Home garden grown rhubarb can be any colour from bright green to bright red and everything in between. Generally speaking the colour doesn't mean much in terms of sweetness. All rhubarb is tart :) I tend to think that thinner stalks of rhubarb are more flavourful, but I'm not sure there's any real evidence of that.
So after all that, use whatever rhubarb you have, red or green, fresh or frozen. If starting with frozen rhubarb, allow a little extra cooking time for your cake.
Brown sugar: This recipe specifies light brown or "golden" sugar. If you only have dark brown or old-fashioned brown sugar, you can use that without issue. Your cake with be a touch darker.
I used white sugar on top, but I think brown sugar would have been a better choice. You can use either.
Cook's Notes for Rhubarb Crumble Cake
This cake takes a while to bake! Mine took almost 1 hour and 30 minutes. Yours may take more or less than that. This is the kind of cake where you should start testing it about the one hour mark and then just keep cooking and testing until it's done.
How to Store the Rhubarb Crumble Cake
This cake kept well stored covered on the counter for several days, though I would say it was at it's best the first 24 hours after baking.
Leftovers, or the whole baked cake can be cooled thoroughly, well wrapped and frozen as well.
Rhubarb Crumble Cake
- 1 cup + 2 Tbsp salted butter (at room temperature)
- 1 1/2 cups light brown sugar
- 2 tsp vanilla extract (or vanilla bean paste)
- 5 large eggs
- 2 1/4 cups all-purpose flour
- 2 tsp baking powder
- 3 cups rhubarb (fresh or frozen, diced)
- 7 Tbsp all-purpose flour
- 1 tsp ground cinnamon
- 1 Tbsp light brown sugar (or white sugar)
- Preheat oven to 325F. Grease and 8-inch springform pan and line the bottom with a round of parchment paper.
- In a large bowl with an electric mixer, or in a the bowl of a stand mixer, fitted with the paddle attachment, beat the butter, brown sugar and vanilla until light and fluffy, about 2-3 minutes. Add the eggs, one at a time, beating well after each addition and scraping down the sides of the bowl several times, as needed. Add the flour and mix, just until combined.
- Remove 1/4 cup of the batter to a small bowl. Add the 7 Tbsp flour and 1 tsp cinnamon and stir together using a dinner knife, until it becomes a crumbly mixture. Set aside.
- Fold the rhubarb into the rest of the cake batter, then spoon the batter into the prepared springform pan, spread to the sides and level the top. Evenly scatter the crumble mixture over-top of the batter, then sprinkle the top with 1 Tbsp of light brown sugar (or white sugar).
- Bake in preheated oven for about 1 hour and 15 minutes to 1 hour and 30 minutes, but check and test regularly after the 1 hour mark and cover the top loosely with a sheet of aluminum foil if the top of the cake is browning too quickly. Bake until a tester comes out clean, as long as that takes. (*If starting with frozen rhubarb, cooking time will be slightly longer).
- Remove from oven and cool for 15 minutes in the tin, then remove from pan and cool completely on a cooling rack.