Keto Rhubarb Pudding Cake – A Warm Dessert You’ll Want on Repeat

Some desserts hit just right. This Keto Rhubarb Pudding Cake is one of those. It’s sweet and tart, creamy and soft, with that little bit of crumble on top that makes you go back for seconds even if you said you wouldn’t. What’s better? It’s low-carb. You can enjoy it without thinking twice about sugar or carb overload.

You don’t need to be on a keto diet to enjoy this one. Even people who’ve never heard the word “keto” ask for the recipe. And that’s what makes this one of the best rhubarb recipes I keep in rotation all year long.

Using Frozen Rhubarb? No Problem.

If you’re not sure what to do with that bag of frozen rhubarb in your freezer, this is one of those frozen rhubarb recipes that actually tastes like something grandma used to make. Frozen rhubarb works just as well as fresh, and sometimes better—because it’s already cleaned and chopped. Just thaw it first and drain off the extra liquid so the cake doesn’t go soggy.

This is the kind of thing you bake when you’ve had a long day and want something warm to eat with a spoon. No fancy steps. No crazy ingredients. It’s one of those easy rhubarb recipes that’ll quietly become your favorite.

What Is Rhubarb Pudding Cake Anyway?

If you haven’t had rhubarb pudding cake before, here’s the deal—it’s soft and gooey at the bottom like a custard or pudding, and cakey on the top. You pour hot water over it before baking, and the magic happens in the oven. Don’t overthink it. Just trust the process. The result is one of those old-school rhubarb desserts that feels like comfort food but fits right into your low-carb goals.

Think of it as a mix between rhubarb pudding and a light rhubarb cake. A little bit of both. The rhubarb melts into the bottom and gets syrupy. The top bakes golden, like a sponge cake, but not too fluffy. It’s warm and rich and just the right amount of sweet.

Ingredients You’ll Need

Everything in this recipe is easy to find. If you’re already cooking keto, you probably have most of it at home. Here’s what you’ll need:

Dry ingredients:

• 1 cup almond flour

• 1/4 cup coconut flour

• 1 tsp baking powder

• 1/4 tsp salt

• 1/2 tsp ground cinnamon

• 1/4 cup powdered erythritol or sweetener of your choice

Wet:

• 2 large eggs

• 1/4 cup melted butter or coconut oil

• 1/3 cup unsweetened almond milk

• 1 tsp vanilla extract

For the Fruit Base:

• 2 cups chopped rhubarb (fresh or frozen and thawed)

• 2 tbsp granulated erythritol

• 1 tbsp lemon juice

For the Pudding Topping:

• 1/2 cup boiling water

• Optional: A splash of heavy cream to drizzle on top when serving

How to Make Keto Rhubarb Pudding Cake

Here’s how it goes—no mixer needed, no drama, just mix, layer, pour and bake.

Step 1: Prep the Rhubarb

Take your frozen rhubarb, thaw it and press out the extra liquid using a clean towel or paper towel. If you’re using fresh rhubarb, just wash and chop. Toss it with the lemon juice and erythritol, then spread it in the bottom of a greased 8×8 baking dish.

Step 2: Make the Cake Batter

In one bowl, mix almond flour, coconut flour, baking powder, cinnamon, salt, and powdered sweetener. In another bowl, beat the eggs, then stir in melted butter, almond milk, and vanilla. Combine the wet and dry stuff. The batter will be thick. That’s fine.

Spoon it gently over the rhubarb layer. Don’t stir it in. Just let it sit on top.

Step 3: Add the Hot Water

This is the weird part that makes it all work. Pour boiling water over the batter—slowly and evenly. Do not mix. It feels wrong, but trust it. The cake bakes into layers: pudding below, cake above.

Step 4: Bake

Slide it into a preheated oven at 350°F (175°C). Bake for 35 to 40 minutes, or until the top is set and golden. A toothpick won’t come out clean—that’s fine. The bottom should still be soft and pudding-like.

Let it cool a bit before serving. Spoon it warm into bowls and if you’re not strict keto, a little cream or low-carb ice cream on top never hurts.

What Makes This One of the Best Rhubarb Recipes?

 

A lot of rhubarb cake recipes can be dry or too tart. This one balances out. The tart rhubarb melts into the sweet base. The texture is soft but not mushy. You get flavor, warmth, and that spoonful comfort that’s missing in most low-carb desserts.

It’s also flexible. Use fresh or frozen rhubarb. Add a few strawberries if you want (still low carb if you keep it under half a cup). Toss in a handful of chopped walnuts for crunch. It’s one of those rhubarb desserts recipes that forgives small changes.

Can You Make This Ahead?

Yes, and it might even taste better the next day. The pudding layer thickens up a bit more after resting overnight in the fridge. Just reheat gently in the oven or microwave. Keep it covered in the fridge and eat within 3 days—though it rarely lasts that long around here.

More Easy Rhubarb Recipes to Try Later

If you’re into rhubarb like I am, you’ll probably want to save more of the best rhubarb recipes. Here are a few simple ones that work just as well with frozen or fresh rhubarb:

• Keto Rhubarb Crisp – Just rhubarb, sweetener, almond flour topping

• Rhubarb Muffins (Low Carb) – Great for breakfast or snacks

• No-Bake Rhubarb Cheesecake Cups – Chill in the fridge, no oven needed

• Rhubarb Compote – Make it once, spoon it on yogurt or keto pancakes all week

These are the kind of easy rhubarb recipes that don’t leave you guessing. Straightforward and useful.

Let’s Talk About Warm Desserts

There’s something different about a warm dessert at the end of the day. Cold cake is fine. Chilled mousse? Sure. But when it’s cold out or you’re just tired, warm desserts feel like home. This rhubarb pudding cake ticks that box.

If you’ve got rhubarb sitting in the freezer or piling up from the garden, don’t overthink it. This one takes under 10 minutes to mix, and the oven does the rest. Make it once, and you’ll see why I keep this on standby every spring.

Tips to Make It Even Better

• Drain Frozen Rhubarb Well – Too much liquid can mess up the texture.

• Use Room Temp Eggs and Milk – Helps everything mix smooth.

• Don’t Skip the Boiling Water Step – That’s what makes the pudding part.

• Taste Before Serving – If your rhubarb’s extra sour, you can sprinkle a bit more sweetener on top.

• Store Covered in the Fridge – Reheat before serving or eat cold if that’s your thing.

Conclusion

This keto rhubarb pudding cake brings together the comfort of rhubarb desserts, the ease of simple prep, and the satisfaction of eating something that tastes way more “cheat day” than it actually is. It works with frozen rhubarb recipes, fits with all your favorite rhubarb cake recipes, and hits that warm dessert spot every time.

Print it out. Save it to Pinterest. Text it to your mom. This one’s worth keeping.

Print