Sugar Free Strawberry Rhubarb Cake

When strawberries and rhubarb are in season …something magical happens. They combine creating a unique flavor combination – tart and sweet. Strawberries and rhubarb are in season at the same time, so it’s only natural that we create some tasty keto dessert recipes using them.
This keto strawberry rhubarb cake is a sugar free upside down cake. The cake is spongy with a hint of lemon flavor. The crumb is moist from the strawberry rhubarb topping that is dripped over it when it is flipped upside down.
Strawberry rhubarb cake is best when you top it with homemade whipped cream or a scoop of keto ice cream. Serve a slice of cake at your next Summer party or for Mother’s Day!
Is Rhubarb Keto?

Rhubarb is a vegetable that is in low in carbs. It has 1.2 net carbs per stalk. Rhubarb is keto approved.
It has a sour, bitter taste but when you contrast it with a sweet fruit like strawberries, it’s delicious!
Are Strawberries Keto?

Most berries are lower in sugar. Strawberries are a keto approved fruit since they are lower in natural sugars. They have 8.7 net carbs per cup of chopped berries.
Strawberries are in season beginning mid May to late June, so take advantage of strawberry season and make your favorite keto strawberry desserts.
My Favorite Keto Sweeteners
The sweeteners that I use in this recipe are Lakanto Classic Monkfruit which is a erythritol and monkfruit based keto sweetener. I also use Lakanto Golden Monkfruit, which is a an excellent sugar-free replacement to brown sugar.
Is Arrowroot Powder Keto?
I like to use arrowroot as a thickener in some recipes. It has 7x the thickening power as flour, so you only have to use a little bit of it to achieve the same thickening effect. Arrowroot powder is a good gluten free thickener option too.
Arrowroot powder does have carbs; however, in this recipe, we are only using 2 teaspoons of arrowroot powder. That contributes to 4 gram net carbs for the entire keto cake. That’s hardly any. Therefore, arrowroot is keto friendly.
Bundt Pan

This is an upside down cake recipe. You can use a regular cake pan if you want to, but I thought using a bundt pan was prettier – especially because I like to make this cake late Spring when strawberries and rhubarb are in season, so around Mother’s Day.
The size of bundt pan I use is a 10 inch pan. You can use smaller if you would like. Remember to spray coconut or avocado oil on the bundt pan before adding the batter so it slides out easy when you flip it upside down.
Keto Cake Ingredient Substitutions
When it comes to the keto diet, everyone has their preference for ingredients – favorite keto flour, favorite sweetener, favorite fat, favorite thickener. Many times people on this low carb way of eating are also battling food sensitivities and allergies as well. Some people need to avoid eggs or nuts. Here are some substitutions you can try if any other these apply to you:
- Nut Allergy: Try substituting the almond flour for sunflower seed flour. You can use the same amount as it substitutes one to one with almond flour.
- Sweeteners: My favorite sweeteners are Lakanto Monkfruit and Swerve Sweetener. You can use any keto sweetener in this recipe as long as it measures cup for cup like sugar.
- Arrowroot Powder: The arrowroot powder serves as the thickener. If you don’t have arrowroot powder, you can substitute with 1 teaspoon of xanthan gum or 1/2 teaspoon of unflavored gelatin.
Light and Fluffy Butter for Keto Cakes

The directions for this sugar free cake state to whip the butter using an electric mixer until the butter is light in color and fluffy. I recommend doing this step because it creates air and volume in the butter which will yield a lighter, spongier cake.
Beat the butter with the mixer until it is fluffy and the color of the butter has changed from yellow to pale yellow or almost white. This step should take several minutes but the end result is worth it!
Keto Strawberry Rhubarb Cake Storage
This cake is best served warm with a scoop of low carb ice cream, so I highly recommend you serve it right away. However, it is still delicious the next day too. I recommend storing the keto cake covered in the refrigerator.