Keto Lemon Tart

Once I figured out how to make a sugar free version of a classic lemon curd, I knew the next mission: a keto version of a classic French lemon tart!

Also known as a tarte au citron, this classic lemon tart recipe features a gorgeous sugar free lemon curd filling, and a keto friendly, gluten free shortbread crust.

While citrus fruits are technically more of a winter thing, this low carb lemon tart is probably one of my top two lemon desserts for summer (the other being my Keto Lemon Bars !)

Actually, it’s probably actually #1, now that I think of it. You just can’t beat that tangy lemon curd, topped with fresh berries.

Yum!

This recipe is actually pretty practical, as well. It lasts 3-4 days in the fridge, but it also freezes well!

I like to wrap individual slices and freeze them, as a quick treat whenever I want it. (Ideally, thaw your slice in the fridge overnight before eating it!).

In terms of dietary numbers, 30.5 grams of carbs per serving come from sugar alcohols, plus 2 grams from fiber. That leaves you with only 3.5 grams net carbs per serving (plus any garnish, if applicable!)

So it’s pretty, delicious, practical, and VERY keto friendly. All around, a great recipe!

Anyway, lets look at what you’ll need for putting on your own keto lemon tart...

Ingredients

If you’ve done any of my keto baking recipes before, you’ll find that this recipe uses really simple ingredients. Whatever you don’t have on hand, you should have no problem finding in any major grocery store... with one possible exception.

Anyway, some notes for you:

Keto “All Purpose Flour” Mix

As with most of my low carb baking recipes, this one uses a combo of Super Fine Almond Flour, Vanilla Whey Protein Powder, and Coconut Flour.

Be sure your almond flour is “super fine”, otherwise you can end up with a gritty texture.

For the vanilla protein powder, just pick something that you like the flavour of, and suits your macros.

Coconut flour... is just coconut flour. Nothing to really add, there!

Allulose

I’m a huge fan of using allulose in my keto baking. Yes, it can be annoying to acquire - I have to order it in from Amazon in the USA - but it’s SO much better than all the alternatives - particularly erythritol.

I hate the weird minty, cooling mouth effect that erythritol causes, and the way it crystallizes can be off-putting. Both of those issues go DOUBLE for this recipe, which involves a lemon curd.

Who wants a cooling, almost minty, crystally lemon curd? Ew.

Anyway, while allulose is the best way to sweeten this recipe, I know you may have your own preferences.

If you’re using a sweetener that’s “cup for cup” style, you’ll need to use a bit less than the amount called for. This is because allulose is a little less sweet than sugar - and the sweeteners designed to sweeten like sugar.

See the notes on the recipe card for the substitution amounts.

Lemons

The lemon filling gets its bright lemon flavor from both fresh lemon juice AND fresh lemon zest. Don’t use bottled lemon juice - it just doesn’t taste right.

This homemade lemon curd was designed using regular lemons, but you can make it with meyer lemons... or even orange juice, for an orange tart.

If you do that, though, you’ll need to add a small amount of citric acid - about ¾ teaspoon for Meyer Lemons, or 1 ¼ - 1 ½ teaspoon for Orange Curd.

This is for two reasons - to give you the perfect balance or sweetness and tartness, AND to help the curd set.

Large Eggs

You’ll need a total of 9 eggs to make this recipe, but only 3 of those are as whole eggs.

You’ll have 6 leftover egg whites. Click here for some recipes that use egg whites, if you're looking for low carb ideas to use up those extra egg whites!

Salted Butter

I use room temperature salted butter. You can use unsalted butter if that’s what you have, you’ll just want to add ¼ teaspoon salt

Garnish

Rounding out this recipe, you should consider garnishes!

I like to use fresh berries and lemon slices to garnish this lemon tart, but unsweetened whipped cream is also great.

If you’re using whipped cream, just add it to the tart slices as they’re served. If it’s not a stabilized whipped cream, it’ll “melt” when stored on a tart.

Equipment

There are only two pieces of more specialized equipment you’ll need for making this keto lemon tart, and really... one of those is somewhat optional.

11" Tart Pan

This recipe was developed for an 11" tart pan with a removable bottom .

While the removable bottom is optional, it definitely makes serving wedges of this lemon tart much easier - and cleaner!

Rolling Pin

While you can press the keto shortbread dough into the tart pan, I like to use a Rolling pin with adjustable thickness guides.

I use it for pretty much anything I use a rolling pin for... well, aside from crushing walnuts!

The guides really help with getting an accurate, consistent thickness to whatever you’re rolling out.

How to Make a Keto Lemon Tart

The full recipe is in the printable recipe card at the end of this post, here is a visual walk through:

Make the Keto Pastry Dough

In a medium bowl, whisk together the almond flour, protein powder, coconut flour, and lemon zest, set aside.

In stand mixer - or in a large mixing bowl if using an electric mixer - cream butter and allulose until fluffy.

Add the egg, beat until everything is fully incorporated and smooth.

Wrap the keto tart dough with plastic wrap, chill for 1 hour.

Note: for best results, don’t skip the chilling step!

Bake the Tart Shell

Heat oven to 350 F.

Spray an 11" tart pan (with removable bottom) with cooking spray.

Use a bit of extra vanilla protein powder to lightly dust your work surface, roll the chilled dough out to about 12" diameter circle.

Carefully place dough in the tart pan. Press dough into the outer edge of the bottom of the pan and into the side scallops of the pan. Aim for an even thickness throughout.

Use a sharp knife to trim the top edge of the crust, discard leftovers.

Prick the bottom of the crust several times with a fork.

Bake crust for 18 minutes, until the lightly golden brown.

Remove from oven and allow to cool to room temperature.

Make the Keto Lemon Filling

Zest 2 of the lemons.

Add the zest and sugar substitute to your mini food processor, blitz until zest is finely chopped and well incorporated in the sugar. Note: See post for details on skipping this step.

Juice your lemons, measuring out ¾ cup of the juice.

In a medium saucepan, whisk sugar mixture with egg yolks, and large eggs until well combined. Add the ¾ cup of juice, whisk until well combined.

Cook this lemon mixture over medium heat, whisking constantly, until mixture thickens. It should be able to coat the back of a spoon and retain a clear trail when a finger is dragged across the back of the spoon.

Ideally, you want the egg mixture to reach at least 165F - I use an instant read meat thermometer for this.

You’ll know it’s ready when the bubbles / foam incorporate into the curd.

If you want to strain the curd, press it through a metal strainer at this point.

Once mixture is thick / hot enough, transfer to a bowl. Add the cold butter, whisking until fully melted and well incorporated.

Once all of the butter has melted in and been fully incorporated into the curd, transfer to your storage container, cover with plastic wrap, and allow to cool to almost room temperature.

Assemble Your Keto Lemon Tart

Pour cooled lemon filling into the baked and cooled tart shell, spread evenly over the bottom of the crust. I like to use an offset spatula to smooth the top.

Cover and chill for at least 4 hours before garnishing, slicing and serving.

Storage and Leftovers

Keto lemon tart will last for 3-4 days in the fridge, or a few months in the freezer. (Thaw overnight in the fridge before use!)

More Low Carb Dessert Recipes

Looking to indulge your sweet tooth with delicious keto desserts that won’t spike your blood sugar? Here are some of my favorite recipes!

Chocolate Cookies
Chocolate Chip Cookies
Chewy Lemon Bars
Chocolate Truffles
Raspberry Coconut Bars
Bananas Foster Truffles
Cheesecake
Fudgy Brownies
Marbled Pumpkin Cheesecake Brownies
Biscotti
Sour Peach Gummies
Ladyfingers
Gluten-Free Rum Cake
Key Lime Cheesecake
Tiramisu
Cream Cheese Mints
Chocolate Mousse
Low Carb Holiday Desserts
Creme Brulee
Carrot Cake

Be sure to see our full menu of sugar free dessert recipes: Keto Dessert Recipes.