This sweet keto rhubarb tart with a crumble topping is the perfect spring dessert. Easy, delicious, and totally sugar-free.
Have I ever mentioned that I am a rhubarb fanatic? I am crazy about that stalky low carb vegetable and I’m always delighted to see its arrival in my local stores.
Yes, rhubarb is indeed a vegetable, although we tend to treat it as a fruit in baking and cooking. It’s a classic for desserts, like my Keto Rhubarb Crisp.
Rhubarb is often paired with strawberries, such as in my Strawberry Rhubarb Dump Cake. But it doesn’t have to be. It’s also amazingly delicious as the star of the show.
And in this delicious keto crumble tart, rhubarb definitely plays the starring role!
Is rhubarb poisonous?
There is a common misconception that raw rhubarb is toxic. In fact, I myself used to think so, because my older brother got quite sick on rhubarb when we were young.
However, the rhubarb stalk is edible raw or cooked. The rhubarb leaves, on the other hand, contain high amounts of oxalic acid and can be toxic.
Most grocery stores and farmers markets sell the stalks only, so there’s little risk of toxicity. If you grow your own, do be careful to cut off all the leaves before cooking.
Keto Rhubarb Tart Inspiration
The main inspiration for this recipe was the rhubarb itself. I’ve been dreaming of rhubarb desserts since February and grabbed a few stalks the moment they hit the shelves.
But I am always saving recipe ideas on Pinterest and I recently spotted this gorgeous tart from The View from Great Island. It was picture perfect!
And with the recent success of my Keto Pumpkin Crumb Cake, I knew I could mimic that delicious crumble topping with my keto friendly ingredients.
How to make Keto Rhubarb Tart
This is an easy keto recipe that results in a delightful dessert. Here are my best tips for getting it right.
I recommend a metal tart pan with a removable bottom, like this one. It helps the crust crisp up properly and it’s easier to get the tart out of the pan.
If you don’t own such a pan, you can make this recipe as crumble bars in a metal 8-inch square pan. You could also use a springform cheesecake pan.
Be sure to grease the pan properly!
This is an almond flour shortbread crust, so it doesn’t contain any eggs. It’s designed to have a crumbly consistency. The coconut flour is important for getting that crumbliness, particularly in the top crust.
Press the bottom crust firmly into the pan so it holds together a little better. Then par-bake it for about 18 minutes. It won’t seem fully cooked at this point but it will firm up as it cools.
Just be sure to let it cool properly!
I know many people want to use the same sweetener for everything and hate when a recipe calls for more than one. But keto sweeteners do not behave like sugar in baking. You need to understand their different properties to get the right results.
The crust takes Swerve because erythritol is the only sweetener that properly crisps up in crusts and cookies. You can just do granulated Swerve if you want.
The filling takes allulose because it helps get the right syrupy consistency without recrystallization. You could use powdered Swerve here but just know that it may become a bit gritty as the tart cools.
Thickening the filling
Like many stalky vegetables, rhubarb releases a lot of liquid during cooking. To avoid making the crust soggy, I recommend pre-cooking it with a little liquid, and then thickening the mixture.
For recipes like this, I like glucomannan to thicken the filling. But xanthan gum or even a little collagen can work too.
Can you make keto rhubarb tart in advance?
This delicious crumble tart is best served fresh. The rhubarb filling does begin to soften the bottom crust after the first day.
That’s not to say it’s not absolutely delicious anyway! I gave a portion to my neighbour and he ate it warmed up for breakfast!
Do store any leftovers in the refrigerator.
More amazing keto tart recipes
- Cannoli Tart
- Keto Butter Tarts
- Tomato Goat Cheese Tart
- Chocolate Macadamia Tartlets
- Keto Cranberry Brie Bites
- Lemon Blackberry Tart
Rhubarb Crumble Tart
Crust and Topping
- Preheat the oven to 325F and grease a 9-inch metal tart pan with a removeable bottom.
- In a large bowl, whisk together the almond flour, sweeteners, coconut flour, cinnamon, and salt, breaking up any clumps with the back of a fork.
- Stir in the butter until well combined. Press about 2/3 of the dough firmly and evenly into the bottom of the prepared pan. No need to go up the sides.
- Bake 15 to 20 minutes, until just golden brown around the edges. Then remove and let cool at least 15 minutes to firm up.
- While the bottom crust is baking, prepare the rhubarb filling.
- In a medium saucepan over medium heat, combine the rhubarb, water, and allulose. Bring to a simmer and cook 5 minutes, until softened and the rhubarb releases some juices.
- Stir in the glucomannan and let cool to room temperature.
- Once the filling is cool, spread evenly over the cooled bottom crust.
- Add the chopped nuts to the remaining crust mixture. Sprinkle the crust mixture over the filling, pressing lightly to adhere.
- Bake another 20 minutes, until the top crust is beginning to brown. Remove and let cool completly in the pan.
- Use a small sharp knife to gently loosen the side of the pan and remove the sides before cutting into slices.