Oh, my darlings, gather ’round! Grandma Rose has a treat for you today that’s just as comforting as a warm hug. We’re making Keto Rhubarb Custard Bars, a delightful low-carb dessert that’ll make your taste buds sing. Rhubarb, with its lovely tartness, combined with a creamy, sweet custard, all nestled on a tender almond flour crust… it’s just like something I remember from my own childhood. And the best part? These bars are guilt-free! So, if you’re watching your sugar intake, or just want a healthier dessert option, you’re in the right place. Let’s get started, shall we?
Why You’ll Love These Keto Rhubarb Bars
Now, you might be wondering, “Grandma Rose, why should I make these Keto Rhubarb Bars instead of your famous regular rhubarb pie?” Well, darling, let me tell you, there are plenty of reasons!
- Low Carb Delight: These bars are perfect if you’re following a ketogenic or low-carb lifestyle. We’re using almond flour and sugar-free sweeteners to keep the carb count down.
- Easy to Make: Don’t let the “custard” part intimidate you. This recipe is simple and straightforward, even for beginner bakers. I promise, you can do it!
- Deliciously Tart and Sweet: The combination of tart rhubarb and sweet custard is a match made in heaven. It’s a flavor profile that’s both refreshing and comforting.
- Perfect for Sharing: These bars are great for potlucks, parties, or just a simple family dessert. Everyone will love them!
- Adaptable: You can easily customize this recipe to your liking. Add different fruits, spices, or extracts to create your own signature version.
Ingredients for Keto Rhubarb Dream Bars
Alright, let’s gather our ingredients. Remember, darling, using good quality ingredients makes all the difference. Here’s what you’ll need:
- 1 ½ cups almond flour
- ¼ cup coconut flour
- ⅓ cup butter, melted
- 2 tbsp erythritol or monk fruit sweetener
- Pinch of salt
- 3 large eggs
- ¾ cup powdered monk fruit sweetener
- ½ cup sour cream or full-fat Greek yogurt
- 1 tsp vanilla extract
- 2 cups chopped rhubarb
- Optional: handful of chopped strawberries

How to Make Grandma Rose’s Keto Rhubarb Custard Bars: Step-by-Step
Now, for the fun part! Follow these simple steps, and you’ll have a batch of delicious Keto Rhubarb Bars in no time. Remember, the secret is patience and a little bit of love.
- Prepare the oven and baking dish: Preheat oven to 350°F (175°C). Line an 8×8-inch baking dish with parchment paper. This will make it easier to remove the bars later, got that?
- Make the crust: In a medium bowl, mix almond flour, coconut flour, melted butter, erythritol, and salt until crumbly. Press the mixture firmly into the bottom of the prepared baking dish. This is your crust, darling.
- Bake the crust: Bake the crust for 10 minutes, or until the edges are light golden. We don’t want it to burn, just a nice light color.
- Prepare the custard: While the crust is baking, whisk together the eggs, powdered monk fruit sweetener, sour cream (or yogurt), and vanilla extract in a separate bowl until smooth. Make sure there are no lumps!
- Add the rhubarb: Gently fold the chopped rhubarb (and strawberries, if using) into the custard mixture. Be gentle, we don’t want to bruise the rhubarb.
- Pour and bake: Pour the custard mixture over the pre-baked crust. Spread it evenly, like you’re tucking the crust in for a nap. Bake for 35–40 minutes, or until the custard is set but still slightly jiggly in the center. It’s okay if it jiggles a bit, it will firm up as it cools.
- Cool and slice: Let the bars cool completely in the baking dish before slicing. This is very important, darling! If you try to slice them while they’re still warm, they’ll fall apart.
Grandma Rose’s Pro Tips for Perfect Keto Rhubarb Custard Bars
Here are a few of my little secrets to ensure your Keto Rhubarb Bars turn out perfectly every time:
- Use room temperature ingredients: This helps the custard mix together smoothly and evenly.
- Don’t overbake: Overbaking will result in a dry, crumbly custard. The custard should be slightly jiggly in the center when you take it out of the oven.
- Cool completely: I can’t stress this enough! Cooling the bars completely before slicing is crucial for a clean cut and a firm texture.
- Use fresh rhubarb: Fresh rhubarb has the best flavor and texture. If you’re using frozen rhubarb, be sure to thaw it completely and drain off any excess liquid.
- Adjust sweetness to taste: If you prefer a sweeter dessert, you can add a little more sweetener to the custard. Just taste it as you go and adjust accordingly.
Common Mistakes to Avoid When Making Keto Rhubarb Bars
Even experienced bakers make mistakes sometimes, darling. Here are a few common pitfalls to watch out for:
- Using too much liquid: If your custard is too runny, it might not set properly. Be sure to measure your ingredients accurately, especially the sour cream or yogurt.
- Overmixing the crust: Overmixing the crust will result in a tough, dense texture. Mix it just until the ingredients are combined.
- Not lining the baking dish: Lining the baking dish with parchment paper makes it much easier to remove the bars and prevents them from sticking.
- Slicing the bars while they’re still warm: As I mentioned before, this is a big no-no! Be patient and let them cool completely.
Variations to Try: Rhubarb Dream Bars Your Way
The beauty of this recipe is that you can easily adapt it to your own tastes and preferences. Here are a few variations to inspire you:
- Add different fruits: Strawberries, raspberries, or blueberries would all be delicious additions to the rhubarb.
- Spice it up: A pinch of cinnamon, nutmeg, or ginger would add a warm, comforting flavor.
- Add nuts: Chopped walnuts, pecans, or almonds would add a nice crunch to the crust or the custard.
- Use different extracts: Almond extract, lemon extract, or orange extract would all complement the rhubarb flavor nicely.
- Make it dairy-free: Use coconut cream instead of sour cream or yogurt for a dairy-free version.
How to Store Your Keto Rhubarb Bars
If you have any leftover bars (which I highly doubt!), you can store them in an airtight container in the refrigerator for up to 3 days. They’re actually quite lovely cold, you know. You can also freeze them for up to 2 months. Just wrap them individually in plastic wrap and then place them in a freezer bag.
Frequently Asked Questions (FAQ) About Low Carb Rhubarb Recipes
- Can I use frozen rhubarb? Yes, you can. Thaw it completely and drain off any excess liquid before using.
- Can I use a different sweetener? Yes, you can. Erythritol and monk fruit sweetener are my preferred choices, but you can also use stevia or another sugar-free sweetener.
- Can I make this recipe dairy-free? Yes, you can. Use coconut cream instead of sour cream or yogurt.
- Can I make this recipe ahead of time? Yes, you can. The bars can be made a day or two in advance and stored in the refrigerator.
- Why are my bars too soft? This could be due to overbaking or using too much liquid. Be sure to measure your ingredients accurately and don’t overbake the custard.
Serving Suggestions for Your Healthy Rhubarb Desserts
These Keto Rhubarb Custard Bars are delicious on their own, but here are a few serving suggestions to elevate them even further:
- With a dollop of whipped cream: A dollop of sugar-free whipped cream adds a touch of elegance and sweetness.
- With a sprinkle of cinnamon: A sprinkle of cinnamon enhances the warm, comforting flavors.
- With a scoop of keto-friendly ice cream: A scoop of vanilla or strawberry keto ice cream would be a delightful addition.
- With a cup of tea or coffee: These bars are the perfect accompaniment to a warm cup of tea or coffee.
And there you have it, darlings! Grandma Rose’s Keto Rhubarb Custard Bars. I hope you enjoy making and eating these as much as I do. Remember, the best recipes are made with love and shared with those you care about. Happy baking!

Keto Rhubarb Custard Bars
Ingredients
Method
- Preheat oven to 350°F. Line an 8×8-inch baking dish with parchment paper.
- Mix almond flour, coconut flour, melted butter, erythritol, and salt until crumbly. Press into dish bottom. Bake 10 minutes until edges are light golden.
- Whisk eggs, powdered sweetener, sour cream (or yogurt), and vanilla until smooth.
- Fold chopped rhubarb (and strawberries if using) into custard.
- Pour custard over crust. Bake 35–40 minutes until set but slightly jiggly in the center.
- Cool completely before slicing.
Notes
