Keto Rhubarb Custard Bars That Actually Taste Like Dessert, Not Diet Food

You know that feeling when you’re craving something sweet but don’t want to wreck your low-carb streak? Rhubarb hits different. It’s tart, bright, and honestly kind of overlooked. And when it’s baked into a creamy custard bar? Pure gold. These Keto Rhubarb Custard Bars are the kind of treat you don’t just eat, you low-key dream about them.

They’re sweet without being loaded with sugar, and they’ve got that rich custard filling that makes them feel like something grandma used to make, except this time, she’s keto.

But let’s back up. If you’ve never had rhubarb before, or if your only memory of it is hiding under a blanket of strawberries in a pie, you’re in for a surprise.

Wait—Is Rhubarb Even Keto?

Good question. Rhubarb is one of the few fruits (okay, technically a veggie) that fits nicely into low carb living. It’s high in fiber, super low in net carbs, and pairs like a dream with creamy stuff—custard, cream cheese, even yogurt.

Most rhubarb desserts recipes go full-on sugar bomb though. Not this one. We’re flipping the script with almond flour, keto-friendly sweeteners, and a silky custard filling that doesn’t skimp on flavor.

This isn’t just some hacked-together low carb rhubarb recipe either. It’s tested, tweaked, and passed the picky family test.

Ingredients You’ll Need

These bars have three main parts: a crust, the custard layer, and a rhubarb topping that melts right into everything. Think of it like the best rhubarb custard cake recipes but in bar form.

For the crust:

• 1 ½ cups almond flour
• ¼ cup coconut flour
• ⅓ cup butter, melted
• 2 tbsp erythritol or monk fruit sweetener
• Pinch of salt

For the filling:

• 3 large eggs
• ¾ cup powdered monk fruit sweetener
• ½ cup sour cream or Greek yogurt (full fat)
• 1 tsp vanilla extract
• 2 cups chopped rhubarb
• Optional: handful of chopped strawberries (for strawberry rhubarb custard bars)

Step-by-Step Instructions (No Stress, No Worries)

1) Preheat and prep

Heat your oven to 350°F. Line an 8×8-inch baking dish with parchment paper, leaving some extra hanging over the sides to make lifting out easier later.

2) Make the crust

In a bowl, mix almond flour, coconut flour, melted butter, erythritol, and salt. Stir until it looks like damp sand. Press it into the bottom of your baking dish and bake for about 10 minutes. You want the edges just lightly golden.

3) Make the custard

While the crust cools a bit, whisk together the eggs, powdered sweetener, sour cream (or yogurt), and vanilla. Don’t overmix. You want it smooth, not bubbly.

4) Add the rhubarb

Toss the chopped rhubarb into the custard. If you’re doing the strawberry rhubarb custard twist, add those too. The strawberries sweeten things up naturally without needing more sweetener.

5) Pour and bake

Pour the rhubarb custard mix over the baked crust. Bake for about 35–40 minutes or until the custard is set but still a little jiggly in the center.

Cool completely before slicing. Seriously, don’t rush this part unless you like mushy bars.

Tips for Better Bars

• Want a swirl like those swirled rhubarb bars King Arthur style? Drop tiny spoonfuls of extra custard on top and use a knife to swirl before baking.
• Go crustless for a low-calorie version. Just bake the custard mix with rhubarb in ramekins.
• Try mixing in cream cheese for cream cheese rhubarb bars. Adds a cheesecake vibe without changing the carb count too much.

What Do these Keto Rhubarb Custard Bars Taste Like?

Think sweet and tart, with a creamy base and a buttery almond crust. The rhubarb softens in the oven but keeps a bit of its bite, which is perfect when it’s balanced by the silky custard. It’s got that throwback rhubarb custard bars recipe energy—like something your mom made for the church potluck but way more keto-friendly.

You won’t believe these are low-carb. Or gluten-free. Or good for you.

What If I’m Not Keto?

Honestly, these bars are great for anyone. Whether you’re counting carbs, watching sugar, doing Weight Watchers, or just trying to eat better, they hit the spot.

They’re packed with flavor, not carbs. So they’re great for rhubarb recipes for diabetics, folks doing low sugar rhubarb recipes, or anyone looking for healthy rhubarb desserts that don’t taste like cardboard.

You can even tweak it for weight watchers rhubarb recipes—just swap out the sour cream for nonfat Greek yogurt and cut the sweetener a bit.

More Ways to Use Rhubarb Without Losing the Yummy in it

If you’re sitting on a bunch of rhubarb from the garden (or your neighbor’s garden because let’s be real, nobody plants just one rhubarb), here are a few more rhubarb easy recipes you can throw together without losing your weekend:

• Low carb rhubarb crisp – Swap oats with almond meal and bake with butter and monk fruit sweetener.
• Rhubarb upside down cake – Use coconut flour cake batter with a rhubarb topping and flip it once baked.
• Savory rhubarb recipes – Simmer chopped rhubarb with onion, garlic, and vinegar to make a tangy sauce for pork or chicken.
• Rhubarb fruit custard recipe desserts – Bake chopped rhubarb in ramekins with cream and egg for a crustless custard bake.

Freezer Friendly? Yep.

These bars freeze surprisingly well. Wrap them up, stash them in a container, and boom—grab-and-go keto dessert anytime. Just don’t try eating them frozen. They need a few minutes to thaw so the custard isn’t rock solid.

What People Are Saying

Real talk from folks who tried this recipe:

“Tastes like something from a bakery—never thought rhubarb bars with custard filling could be low carb.”

“Added strawberries and cream cheese… basically made strawberry rhubarb custard bars with a cheesecake layer. Obsessed.”

“Even my dad, who thinks keto is ‘hippie food,’ went back for seconds.”

Why This Recipe Works for Everyone

It hits all the right buttons:

• Looks good – Pink rhubarb on creamy yellow custard, sliced clean, perfect picture sharing.
• Real ingredients – Nothing weird or hard to pronounce.
• Easy to Find – Like rhubarb desserts recipes, low carb rhubarb recipes, gluten free rhubarb, and rubarb deserts bars (yes, even the typo—some people search like that).

Conclusion

These keto rhubarb custard bars are more than a dessert. They’re your answer to the “I want something sweet but not sugary” craving. They’re simple to make, look impressive, and taste like you spent way more time than you did.

You can go fancy or keep it basic. Either way, they hit. Whether you’re baking them for your next family brunch, a potluck, or just to treat yourself mid-week, they’re going to disappear fast. You’ve been warned.

Oh, and if you’re looking to explore more best rhubarb desserts, keep this recipe on repeat. It’s got that cozy, nostalgic flavor with modern-day macros.

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