Quick And Easy Rhubarb Snack Cake With Brown Sugar Topping.

This fantastic spring rhubarb snack cake is so tasty. Made with simple pantry ingredients, the easy rhubarb cake whips up in a flash in one bowl, making it the perfect dessert to use up that spring perennial plant. Your entire family will ask for this brown sugar-topped soft crumb rhubarb cake year after year. It is that good.

Years ago, I planted a small patch of rhubarb in my garden. I then realized I needed new ways to use the fruit besides jam and crisp. Don’t get me wrong; those are tasty options, too. But when you have a freezer surplus of the tart red rhubarb stalks cut up into bite-sized pieces from last year to work with, you tend to get a bit creative. 

This cake became so popular with my kids growing up that it became a yearly tradition to make it every rhubarb season. I will not lay claim to having concocted this baking recipe myself. I found the recipe in a local church cookbook. The original recipe’s author is a local churchgoer who happened to have a wave of genius. Because this recipe always comes out perfectly. It’s the ideal way to use up your extra rhubarb.

​If you want to find more favourite rhubarb recipes, try our delicate rhubarb scones with strawberry rhubarb jam. 

Why you will love this recipe

It’s fast and straightforward. This sweet rhubarb cake recipe can be tossed together in one bowl in as little time as ten minutes. 

The sweet cinnamon sugar topping. It is just the perfect addition to the soft cake. It adds the right balance of sweetness to the tart rhubarb, so you will want to have a big slice! 

Great for potlucks. The rhubarb snack cake makes a large nine-by-thirteen panful of delicate cake ideally suited to take along at your next potluck or church gathering. It’s also rather poetic that a churchgoer’s recipe returns to a church supper. 

Let’s get that rhubarb out of the freezer!

Okay, so you don’t have to use frozen rhubarb, but if you do, it works out well either way. Fresh fruit, if you are using it, is sweetest when the stalks are pink to red and small. The larger the stalk, the stringier it becomes and the more tart it becomes. So, if you want tart, go green; if you like sweet, go pink/red. And if you want to be in the middle of the road, use a mix of rhubarb stalks. 

If you use frozen rhubarb, dust the frozen rhubarb with flour before adding it to the cake batter. Putting it in a small bowl with two rounded tablespoonfuls works beautifully to coat the fruit.

You will begin by mixing the oil with the sugar in a large bowl. I said I didn’t alter the recipe, but the original recipe asks for butter or margarine. I, however, prefer neutral oil in cakes as it makes them extra light and fluffy. I find that butter can make a cake heavier. 

Blend the oil, sugar, then add the egg blending well. Drop the vanilla in before measuring the dry ingredients in another bowl. You can then add the dry ingredients to the wet and start to blend together. You will also need to prepare the sour milk for this stage. To make sour milk easily at home, add a tablespoon of white vinegar to regular milk. You can slowly add the sour milk as you blend the flour into the wet ingredients. 

Continue mixing the cake batter until there are no more lumps. This is one cake I have yet to overmix, so don’t be shy about mixing the heck out of the batter. 

The next step is measuring the rhubarb. Again, frozen rhubarb should be dusted in flour to prevent the extra moisture from affecting your cake. Once the rhubarb has been blended into the cake batter, go ahead and pour the batter directly into a prepared nine-by-thirteen pan. I use simple cooking spray, but oiling your cake pan with neutral oil or butter will also work. 

Lastly, before baking, you need to make the brown sugar topping. This isn’t a streusel topping, as it has no flour. Instead, it’s a brown sugar, softened butter, and cinnamon mixture. It’s easier to use soft butter to mix the dry ingredients.

Drop the brown sugar mixture over the unbaked cake in the pan using your clean hands. You won’t cover the entire cake; instead, drop it here and there. Once all the brown sugar toppings have been dropped onto the cake, it’s ready for the oven. 

The preheated oven should be set to a standard cake temperature of 350 degrees Fahrenheit. Pop that cake in for a full 45 minutes to bake. Test your cake for doneness with a cake tester. Or, if you don’t have one, insert a butter knife into the cake near the center, where it takes the longest to bake.

Before you do, make sure the cake doesn’t look wet. If it appears wet, it likely isn’t done, and sticking it with the butter knife will result in it potentially falling. If it seems baked, it will be a deep golden brown, and you can slide the butter knife into the cake easily.

A clean butter knife indicates the cake has been fully baked. If there is moist batter, it’s not cooked fully; a bit of moist batter means a few more minutes. This handy method has stood the test of time, as I have been baking for over 40 years—eek, I am aging myself. I learned this technique from my mother while we baked in our woodstove. 

Serve the cake cooled or warm in large squares. This cake has a beautiful, tender crumb, and the brown sugar topping sinks into the cake’s surface, making sweet pops of sugary cinnamon burst into the moist cake. This is the perfect recipe for any rhubarb lover to enjoy. It’s one of my family’s favorite rhubarb recipes. 

Ingredients:

All-Purpose Flour: This flour has a moderate protein content, making it ideal for most baked goods. I use it mainly because I bake so much, and purchasing a super-sized bag is a very economical choice. 

White Sugar: This sugar will make that beautiful light crumb while sweetening the tangy rhubarb. White sugar also keeps the cake light, which looks beautiful against the darker sugar topping. 

Egg: I use large eggs when baking. The egg helps with this recipe’s structure, moisture content, and leavening. Have you ever made a cake and noticed how much lighter the butter-sugar mixture is once it’s whipped with an egg? The egg creates an airy mixture that helps make your baking so light and fluffy. 

Vanilla Extract: This extract is perfect for balancing and enhancing flavors, giving your cake a depth of flavor. 

Rhubarb: This springtime plant is the perfect fruit for making this cake. The tartness of the rhubarb brings a spritely flavor to the sweet white cake. 

Oil: I used oil in this cake instead of butter because it creates a lighter cake crumb. It also adds a bit more moisture to the resulting cake vs butter. 

Baking Soda: This leavening agent is essential for the rise of your cake. Although just a snack cake, it needs to rise to be light and airy. 

Salt: This ingredient is often found in baking. I used to think it was just for leavening; however, I have learned that salt also helps to enhance and balance flavors. Furthermore, salt is a preservative helping extend the shelf life of your baked goods.

Sour Milk: This can be made easily at home by adding a tablespoon of white vinegar to regular milk. There is no need to purchase a special ingredient just for one recipe. I love that!

Cinnamon: This warm spice originated in Sri Lanka (formerly known as Ceylon), an island country in South Asia. Its robust flavor perfectly balances the tart of the diced rhubarb in this cake. 

Substitutions and Add-Ins:

All-Purpose Flour: When substituting alternative flours for all-purpose flour in a rhubarb snack cake, remember that the final product’s texture and flavor may vary slightly depending on the flour used. Some suitable flour alternatives are pastry, spelled, or oat flour. You can also get away with using a mixture of whole wheat and white. 

White Sugar: As stated, this recipe was from a local church cookbook. I follow the original recipe closely because, well, it works, and it’s delicious. If you do want to test a different sweetener with the rhubarb cake, I recommend testing out Monk fruit sweetener; note it is considerably sweeter than white sugar, so you may need to play around to find the correct amount to use. Alternatively, you can switch out the white sugar with stevia. Again, it’s a sweeter natural choice than that, so only a small amount is needed. If you aren’t overly concerned about the light cake crumb, switch the sugar to brown or coconut. 

Egg: If you have an egg allergy or are vegan, using a flaxseed egg or other egg alternative may work with this recipe. Please note that I have not tested this recipe with egg substitutions. 

Vanilla: You can omit the vanilla extract if you’re all out. It will slightly change the outcome, but only by a little. I have made the cake with and without it and have no complaints. 

Rhubarb: I used my frozen rhubarb to make the cake seen in the pictures. However, you can easily use your fresh rhubarb crop to make this seasonal cake. Add apple instead of rhubarb for a great fall snack cake if you want to experiment.

Oil: The original recipe calls for butter or margarine. I prefer oil in cakes and muffins for a lighter crumb. It’s also much more economical to bake with a neutral oil vs butter, which has skyrocketed in recent years. If you wish to try the cake with butter or margarine, feel free to do so. The ratio remains the same either way. Be sure to leave a comment after the recipe card, so I know how it turns out!

Baking Soda: This important leavening agent can be replaced with baking powder in this cake recipe. Replace one baking soda with three teaspoons (1 tablespoon) of baking powder. 

Salt: This ingredient may seem insignificant since it is only half a teaspoon. Still, it’s essential, so please leave it in the recipe. 

Sour Milk: This ingredient can be purchased in the store, or you can make it yourself by adding a tablespoon of white vinegar to your regular milk. You may think using Greek yogurt or sour cream would be all right. However, I don’t recommend using them as this cake is already very moist, and also, because yogurt and sour cream have a tang to them that will throw the sweetness balance off in this rhubarb cake. Remember, too, that rhubarb is tangy all on its own; adding more tang to the cake will likely go wrong. 

Cinnamon: This warm spice is in the cake’s brown sugar topping, adding flavor and warmth to the springtime dessert. However, if you want to mix things up a bit, other spices that also are warm choices are nutmeg (although this one is much stronger than cinnamon and not everyone’s cup of tea, so use it sparingly with cinnamon), chai or allspice. Before adding a different brown sugar topping spice blend to the whole cake, taste it to be sure you are happy with its flavor profile. It’s too late to remove it once it’s on the cake batter. 

Expert Tips With Serving and Storing Suggestions:

Tip #1: Use All The Topping. It may seem like a lot of heavy glops on your cake batter, but it’s delicious when the buttery brown sugar topping sinks into the cake as it bakes. I’ve made it with less, and you miss the extra sweetness. 

Tip #2: Cut Rhubarb Small. Don’t use overly large pieces of rhubarb in the cake. Each piece should be a half-inch in size at most. 

Tip #3: Flouring the rhubarb. If it’s frozen, this additional step is super important for the rhubarb to soak up the extra moisture and keep it from sinking in the batter. Flouring the fruit helps it to suspend in the batter while baking, ensuring each bite is perfect!

This great recipe can be served warm, fresh from the oven, with a cup of coffee, or chilled as a snack cake in your lunchbox. Either way, the sweet tang of the rhubarb mingles with the cinnamon brown sugar topping, making each mouthful of tender cake a blissful experience any time of day. It’s such a great way to use up your frozen rhubarb! 

Cake can be left out if you cover it with plastic wrap or put it in a cake container to stay fresh! The cake is so moist that it lasts up to five days. If you’ve got too much cake for your family, you can freeze it for up to three months. I doubt it will make it to the freezer, though—it’s that good!

​Have you tried baking this tasty springtime rhubarb cake? We’d love to know what you think. Please leave a comment below the recipe card.