Gluten Free Rhubarb Cake with Buttermilk

This Gluten Free Rhubarb Cake is moist and made with buttermilk! It's flavored with citrus zest and baked with a cinnamon sugar topping.

When it comes to springtime desserts, it doesn't get any better than this Buttermilk Rhubarb Cake! It's an old fashioned dessert that's perfect served with some coffee or tea.

Every year when the rhubarb patch appears at the edge of our garden, I find myself craving desserts like this rhubarb cake. This recipe is based on one found in my favorite old church cookbook. It's one of those old fashioned cakes that calls for simple ingredients and requires no fancy cooking techniques.

You can use fresh or frozen rhubarb when making this cake. The tartness of the rhubarb is balanced out with some brown sugar. The texture of the cake is moist because it's made with buttermilk, which also provides another layer of flavor.

The batter is flavored with both orange and lemon zest, which brighten the whole thing up and adds a floral note and the cake is then baked with a cinnamon sugar topping, which provides a little bit of crunchy texture.

It's not overly sweet or tart. This cake is nicely balanced and easy to prepare. It will definitely get you excited for rhubarb season!

Jump to:

• What Is Rhubarb?
• Should I Use Fresh Or Frozen Rhubarb?
• What Is Buttermilk?
• How To Make Your Own Buttermilk
• Ingredients For Gluten Free Rhubarb Cake
• How To Make Gluten Free Rhubarb Cake
• Combine The Wet and Dry Ingredients With Buttermilk
• Do I Need To Cook Rhubarb Before Baking?
• How Long Does Rhubarb Cake Take To Bake?
• What To Serve With Rhubarb Cake
• How To Store Rhubarb Cake
• Can This Cake Be Frozen?
• Gluten Free Rhubarb Cake with Buttermilk

What Is Rhubarb?

Every year come late spring a small patch of rhubarb pops up at the edge of nearly every garden in the state of Minnesota and the Great Lakes region.

It's ubiquitous in these parts and can be found in desserts lining the serving tables at potlucks and picnics during the summer months.

Rhubarb is a perennial vegetable that consists of long stalks that are green and red or pink in color and and topped with bushy dark green leaves.

It has a tangy, almost sour flavor and is often added to desserts along with sugar to balance it out. Rhubarb is perfect in sweet dishes like pies, bars, and crisps and can also be used to make syrups, jams, and compotes.

Rhubarb is sometimes utilized in savory dishes and used to make sauces, dressings, and chutneys. It can also be pickled and used as a condiment.

The stalks are the only edible part of the rhubarb plant - the leaves are poisonous as they contain oxalic acid and may not be eaten. Make sure to remove the leaves and discard if using fresh rhubarb!

Should I Use Fresh Or Frozen Rhubarb?

The great thing about rhubarb is that it can be enjoyed fresh or frozen.

As is the case with most produce, it's best to use fresh rhubarb if possible. Fresh rhubarb may be harvested straight from the garden or purchased in the produce section of your local grocery store when in season or at a farmer's market.

Given the short growing season many folks choose to freeze their rhubarb in order to preserve it throughout the colder months. Alternately, it may be available in the freezer section of your local grocery store.

The one thing to keep in mind is that frozen rhubarb contains more water than fresh rhubarb and needs to be both thawed and drained before adding to the cake batter. If not properly drained, the frozen rhubarb may cause the batter to become watery.

• If using frozen rhubarb, simply place it in a strainer and thaw for a few hours before use.
• Once the rhubarb is thawed, place it in between a few paper towels or kitchen towel in order to absorb any excess moisture.
• After the thawed rhubarb has been patted dry, dice and use just as you would fresh.

What Is Buttermilk?

Buttermilk is a fermented dairy product that has a thick texture and slightly tangy flavor. It can be used in both sweet desserts and savory dishes.

Buttermilk provides baked goods with a moist texture and a bit of tangy flavor. It gives things like buttermilk pancakes and buttermilk biscuits their distinct flavor.

The acidity in buttermilk makes it a great choice for marinating meats like chicken, as it helps to break down the proteins and creates a tender, juicy piece of meat.

I love to use buttermilk in both sweet and savory dishes for both the taste and texture it provides. It's added to everything from bread pudding to sweet potatoes in my kitchen.

How To Make Your Own Buttermilk

Don't have any buttermilk on hand? You can make your own by simply combining some milk and a bit of lemon juice or white vinegar!

1. To make your own buttermilk, pour 1 Tbsp. of lemon juice or white vinegar into 1 cup of milk.
2. Allow the mixture to sit for 10 minutes at room temperature, stir the mixture, and use as needed.

Ingredients For Gluten Free Rhubarb Cake

Here's what you'll need to make it.

• 1 ½ packed cups Brown Sugar
• ½ cup Unsalted Butter (softened, but not melted) (equals 1 stick)
• 1 cup Buttermilk
• 2 Eggs
• ½ tsp. Kosher Salt
• 1 tsp. Baking Soda
• 2 cups Chopped Rhubarb (fresh or frozen)
• 2 cups Gluten Free Flour Blend (or AP flour if not gluten free)
• 1 Lemon (zest only)
• 1 Orange (zest only)
• ¼ cup Sugar
• 1 tsp. Cinnamon

In general, it's best to use unsalted butter when baking. This allows you to control the amount of salt in your recipe and won't change the overall flavor profile of the cake.

The butter used to make this cake should be softened, but not melted. Feel free to let it sit at room temperature for a few hours to soften.

How To Make Gluten Free Rhubarb Cake

This is an easy cake recipe that's made by first combining the wet and dry ingredients in separate bowls. The wet and dry ingredients are then combined along with the buttermilk.

The chopped rhubarb is then added to the batter, which is spread out into a greased 9x13 inch baking dish, sprinkled with a cinnamon sugar topping, and baked for 38-40 minutes at 350 degrees Fahrenheit.

1. Start by finely chopping 2 cups of fresh rhubarb. If using frozen rhubarb, make sure to thaw, drain, and pat dry before chopping. Set aside.
2. In one bowl, add 1 ½ packed cups brown sugar along with ½ cup (equals 1 stick) of softened, but not melted unsalted butter. Cream the butter and brown sugar using a hand mixer on medium speed for 1-2 minutes, or until the mixture is completely combined.
3. Add 2 eggs to the butter and sugar and mix for another 30 seconds or so on medium speed (the mixture will be kind of thick and sticky).
4. In a second bowl, add 2 cups of gluten free flour blend (or regular AP flour if not gluten free), 1 tsp. baking soda, and ½ tsp. kosher salt. Stir until completely combined.

Combine The Wet and Dry Ingredients With Buttermilk

Once the wet and dry ingredients are ready, it's time to combine them along with the buttermilk.

It's best to add the dry ingredients to the wet and do this alternately with the buttermilk so that everything is combined evenly.

1. Measure 1 cup of buttermilk.
2. Add half of the dry ingredients to the wet and stir until combined. Add ½ cup of buttermilk to the batter and stir until combined.
3. Repeat with the second half of the dry ingredients and then the other ½ cup of the buttermilk.
4. Stir the batter until completely combined.

Do I Need To Cook Rhubarb Before Baking?

There is no need to cook the rhubarb before adding to the cake batter.

1. Once the batter is ready, add 2 cups of finely chopped rhubarb.
2. Using a Microplane or small zester, zest 1 orange and 1 lemon.
3. Add both the orange and lemon zest to the batter along with the diced rhubarb. Fold the rhubarb and citrus zest into the batter until it is evenly combined.

The lemon and orange zest add a slight citrus note to the cake and make the whole thing nice and fragrant.

How Long Does Rhubarb Cake Take To Bake?

Once the batter is ready, it's poured into a greased 9x13 inch baking dish and baked for 38-40 minutes at 350 degrees Fahrenheit.

It's important to grease the baking dish properly so that the cake doesn't stick to the surface as it bakes in the oven.

Before baking, the top of cake is sprinkled with a mixture of cinnamon and sugar, which provides the cake with a little extra sweetness and a slightly crispy texture.

It's best to use glass baking pans, metal pans with a protective coating, or a nonreactive pan, as rhubarb is acidic and can cause discoloration to metal cookware.

1. Heat oven to 350 degrees Fahrenheit.
2. Grease a 9x13 inch baking dish generously with butter or cooking spray.
3. Spread the batter evenly across the bottom of the baking dish (the batter will be kind of sticky).
4. In a small bowl, combine ¼ cup sugar and 1 tsp. cinnamon.
5. Sprinkle the cinnamon sugar mixture evenly over the top of the cake.
6. Place the cake in the oven and bake for 38-40 minutes.
7. Remove the baking dish from the oven and allow the cake to cool before serving.

Baking times may vary slightly depending on the type of cake pan and oven used. I found 40 minutes to be perfect but baking times may be different for you.

To test if the cake is done, place a toothpick in the center. If the toothpick is clean when removed then the cake is ready.

The top of the cake should be golden brown when finished.

What To Serve With Rhubarb Cake

This Gluten Free Rhubarb Cake is great because you can serve it for dessert after dinner or for breakfast with coffee or tea.

The texture is moist and springy. It's somewhere between a coffee cake and a sponge cake.

This cake can be served as-is, or topped with some homemade whipped cream, creme Anglaise, or ice cream.

For a healthier topping, you can opt for yogurt or Greek yogurt.

Feel free to garnish with some nuts like almonds or walnuts for extra crunch.

How To Store Rhubarb Cake

To store rhubarb cake, all you need to do is allow it to come to room temperature and cover the cake pan with a tightly fitted lid or a dish towel so that it doesn't dry out.

It should last 2-3 days stored in an airtight on the counter at room temperature.

You can also store it in the refrigerator for 2-3 days if you prefer. Make sure to store the cake in an airtight container so that it doesn't dry out.

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Can This Cake Be Frozen?

Yes! This Gluten Free Rhubarb Cake can be frozen.

How To Freeze

1. Prepare the recipe as directed and allow the cake to cool completely before freezing.
2. Wrap the cake tightly in plastic wrap or cling wrap. Then, place the wrapped cake in a heavy-duty freezer bag or tightly wrap it in foil.
3. Label with the date and store up to 3 months.

How To Thaw

1. Place the cake in the refrigerator 12 hours before serving.
2. You can also thaw it on the counter top for a few hours if preferred.

If you like this Rhubarb Cake, you'll love this Cinnamon Sugar Apple Cake!

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