Name: Keto Rhubarb Cake
Prep time: 10 min
Cook time: 60 min
Total time: 100 min
Ingredients: 1 cup / 140g rhubarb (diced ); 1/4 cup / 50g granulated sweetener (for macerating (soaking)); 4 eggs (large, room temperature); 1/2 cup / 114g butter (melted, then cooled); 1/4 cup / 60g cream cheese; 1/4 cup / 60ml almond milk; 1/2 cup / 100g granulated sweetener (use up to 2/3 cup if you like a sweeter cake); 2 cup / 200g almond flour; 1/4 cup / 30g coconut flour; 2 tsp baking powder; 1 tbsp vanilla extract; 1 tsp almond extract (optional); 1/2 cup / 50g almond flour; 1 tbsp coconut flour; 2 tbsp butter (melted); 1 1/2 tbsp granulated sweetener; 1 tsp cinnamon

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This keto rhubarb cake offers three layers of gorgeousness: a moist yet light and fluffy vanilla crumb, a sugar free rhubarb filling and a delicious cinnamon streusel topping. It's a cake recipe the entire family will enjoy, whether they are on a low carb diet or not! Only 10 minutes prep.

taking a slice of keto rhubarb cake from a cake on a cake stand

Even though I have lived in London for more than half my life now, I'm not doing high tea in the afternoon. True to my German roots, I am more of a "Kaffee und Kuchen" person. Coffee and cake, that's what Germans do in the afternoon.

In my home town Hamburg, you'll get invited to a "Kaffeeklatsch", which loosely translates into "coffee gossip". Which is where this cake comes in! I have grown up with rhubarb cakes (we always grew rhubarb in the garden) and really wanted to make my own sugar free version.

This cake is one of my favourite keto rhubarb recipes. I love a good crisp or crumble, and I'm known for my keto rhubarb muffins. I'll post both soon. But now, let's get going with today's recipe!

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Ingredients
Instructions
Baking Times
Recipe Variations
Serving Suggestions
Storage
More Keto Cake Recipes
Recipe

Ingredients

Here are the ingredients you'll need:

Rhubarb
Eggs - these should be large and room temperature
Butter, cream cheese and almond milk
Granulated sweetener - I used a golden erythritol monk fruit blend, but a granulated white sweetener will work just as well. This cake is gently sweet - add up to ⅔ cup sweetener if you prefer.
Almond flour - I'm using what we over here in the UK call ground almonds. This is equivalent to regular almond flour in the US. If you're using super-fine almond flour, I would reduce the amount by 2 tbsp.
Coconut flour - because it complements almond flour just so well in gluten free low carb recipes.
Plus baking powder, vanilla extract, cinnamon for the streusel and optional almond extract for the cake batter.

Instructions

This section contains step-by-step instructions and photos that show how to make this recipe. See the recipe card for full information on ingredients and quantities

Prepare the rhubarb: If the stalks are thick and woody, peel and cut them into thinner slices, about a finger thick. Then chop into 3-5 cm long pieces and mix with the sweetener. Let the mix sit for 30 minutes to macerate.

This process draws out excess liquid and prevents the cake from becoming soggy. You'll end up with a fair amount of liquid in the bowl!

frothy whisked eggs in a bowl with a blender

Sugar free cake batter: Now, beat the eggs until pale, fluffy and double in size. This should take about 2 minutes.

Add the sweetener, melted and cooled butter, cream cheese, almond milk vanilla extract and almond extract (if using). Continue beating for another 1 minute.

mixing almond flour and coconut flour into the egg mix with a blender

Mix the almond flour, coconut flour and baking powder in a separate bowl. Then add them to the wet ingredients and blend until you have a smooth batter.

It should look like this!

Cinnamon streusel: Next, mix the streusel. No separate pic for this, just mix all ingredients in a separate bowl using a fork (and try not to eat all of it straight away - it's super yum).

And now let's assemble this rather awesome keto rhubarb cake!

rhubarb pieces on cake batter in a springform

Fill the cake batter into the prepared springform. Arrange the rhubarb pieces in a single layer over it...

streusel on rhubarb pieces in a springform

... and top everything off with the sugar free streusel mix.

Baking Times

I baked my cake on the middle shelf for 63 minutes in total. I've given you a range of 60-65 minutes.

Check with a skewer or knife that the middle is baked and not wet, keeping in mind that the rhubarb will be soft and sticky.

Most importantly, check the cake after 35-40 minutes. If the streusel have browned sufficiently, loosely cover it with a piece of aluminium foil to prevent burning.

Overhead view of the streusel cake decorated with rhubarb pieces

Baking in other cake pans

If you use a different sized baking pan be aware that the baking time will differ.

The first time around I baked this cake in a small 18 cm / 7 inch springform, which increased the oven time by 10 minutes.

A larger round or rectangular pan will need less time - probably only about 40-45 minutes. Basically, the flatter the cake is, the less oven time it needs.

Whichever pan you use, let the keto rhubarb cake cool completely before releasing it from the springform. Low carb cakes are fragile when hot and firm up as they cool.

To ensure it does not break or split, run a knife around the edges before you open the form.

a slice of rhubarb cake with streusel on a plate with a fork and the cake on a cake stand

Recipe Variations

No coconut flour - To make this cake without coconut flour, replace it with 3x the amount of almond flour.

Dairy free - For a dairy free keto coffee cake, replace the butter with coconut oil and the cream cheese with coconut cream.

Using different fruits - This cake would work well with berries. Try using my Easy No-Cook Sugar Free Raspberry Jam as a filling! Or add a few strawberries for a keto strawberry rhubarb cake.

Serving Suggestions

Sugar free icing - Want to go the extra mile? Top the crumbles with a vanilla flavoured sugar free drizzle! Simply mix 2 tablespoon almond milk with 4 tablespoon powdered sweetener and ½ teaspoon vanilla extract until you have a thick, but pourable consistency.

Fill into a ziploc bag, cut off a little corner and drizzle the icing over the cooled cake.

Alternatively, serve with a dollop of Sugar Free Keto Whipped Cream or a scoop of Sugar Free Low Carb Ice Cream.