Keto Rhubarb Lemon Meringue Squares

Keto Rhubarb Lemon Meringue Squares. A simple but elegant low-carb dessert that celebrates rhubarb. The base is moist and lemony, the filling is a sweet-tart rhubarb custard, and the topping is a light, fluffy meringue.

Although it has three layers, this dessert is straightforward to prepare and tastes far more impressive than the effort involved.

This version comes from a family recipe collection my aunt compiled. It was originally called “Spring Rhubarb Dessert” and was noted as a favorite of my Uncle Art. I adapted it to be keto-friendly and kept the bright citrus and rhubarb flavor that makes it memorable.

Everyone who tried it loved it — my sister and even my picky 21-year-old son thought it was excellent. I’m confident you will enjoy it too.

Can I Eat Rhubarb on Keto?

Rhubarb is a vegetable often used like a fruit in desserts such as pies and crumbles. It’s keto-friendly: one cup of diced rhubarb contains about 26 calories and roughly 3.3 net carbs, making it a great option for low-carb baking while still offering that bright, tart flavor.

So yes — rhubarb fits nicely into a ketogenic diet when used in moderation.

Gather These Items for this Low Carb Rhubarb Dessert Recipe

Food ingredients:

Rhubarb
Lemons
Almond flour
Zero-carb sweetener (monk fruit or other keto-friendly sweetener is recommended)
Eggs

Tools and equipment:

Lemon zester
Electric mixer for whipping egg whites
Pot or saucepan for the filling
Mixing bowls
9 x 13-inch pan

Tips and Tricks for Making Keto Rhubarb Lemon Meringue Squares

If you don’t have an orange, substitute two lemons for a bright citrus flavor — the original recipe used orange but lemon works beautifully.
You can make the rhubarb custard a day ahead and refrigerate it until you’re ready to assemble and bake.
Cream of tartar helps stabilize meringue, but if you don’t have it the meringue can still turn out well if whipped properly.
After baking, cool completely, then refrigerate. Chilling allows the lemon flavor to meld into the base, delivering a moist, delicious square.
If you use regular sugar, note that the original recipe used larger sugar amounts that were reduced here for keto. Adjust sweetness to taste based on your chosen sweetener.

Keto Rhubarb Lemon Meringue Squares Printable Recipe Card

Yield:
24

Prep Time:
15 minutes

Cook Time:
30 minutes

Total Time:
45 minutes

Keto Rhubarb Lemon Meringue Squares. A simple yet elegant low-carb dessert with a moist lemon base, a sweet-tart rhubarb custard, and a fluffy meringue topping.

Ingredients

Bottom Layer

1 1/2 cups almond flour
1/4 cup sweetener
1/2 cup softened butter

Filling

4 cups sliced rhubarb
2 tbsp butter
1 cup sweetener
Zest and juice of 2 lemons
3 egg yolks, beaten (reserve whites)

Topping

3 egg whites
1/4 cup sweetener
1/2 tsp cream of tartar (optional)

Instructions

Blend almond flour, sweetener and softened butter to form the base dough.
Press the mixture into the bottom of a 9 x 13-inch pan.
Bake at 350°F (175°C) for about 10 minutes.
While the base bakes, combine sliced rhubarb, lemon juice and zest, and butter in a saucepan. Bring to a boil, stir in sweetener, then simmer until slightly thickened. Remove from heat and stir in the beaten egg yolks to create the custard filling.
Spoon the rhubarb filling evenly over the baked base.
Whip the reserved egg whites with cream of tartar (if using) and sweetener until stiff peaks form.
Spread the meringue over the rhubarb filling, covering it completely.
Bake at 350°F (175°C) for 15–20 minutes, or until the meringue turns a light golden color.
Cool completely, then refrigerate before serving to let flavors meld and the dessert set.

Notes

If you substitute regular sugar, be aware the original, non-keto recipe used higher amounts: 1/4 cup in the bottom layer, 1 1/4 cups in the custard layer, and 1/3 cup in the meringue.