Billowy marshmallow meringue adds a fluffy texture to these zesty lemon bars. The rich, buttery crust and tangy lemon curd filling are complemented with a lofty marshmallow meringue. Lemonheads will appreciate their delicious sweet-tart flavor and textures, and even if you aren't one, I bet you will still enjoy the contrast in flavor!

What is cream of tartar?
It's not creamy, to begin with. It's a dry, powdery, acidic by-product of grape wine fermentation. Its scientific name is potassium bitartrate (hence the commercial name), which comes from potassium hydrogen tartrate or tartaric acid. However, it's usually called cream of tartar in the spice aisle.
Adding a little bit of cream of tartar to egg whites while beating—usually ⅛ teaspoon per egg white—not only speeds up the formation of foam, but it also helps to keep the structure of those tiny air bubbles you're creating. This means mile-high meringue pies, melt-in-your-mouth meringue, and other delicious fluffy cakes.
How do you brown meringue?
One of the most recognizable features of meringue is the browned top but how do you achieve that? If you have a broiler function on your oven, this will work nicely to do the job. But there is another way - a handheld kitchen torch!
Like a small fire lighter, these devices are used for different jobs around the kitchen, are inexpensive to buy, and are easy to use. One of the perfect examples of what they do is to brown the mixture on the top of the meringue to create that brown touch looks we all want.
What you need to make lemon meringue bars
For the Crust
- All-purpose flour
- Confectioners' sugar
- Unsalted butter
- Salt
For the Filling
- Large eggs
- Large egg yolks
- Granulated sugar
- Grated lemon zest
- Fresh lemon juice
- Salt
For the Meringue Frosting
- Large egg whites
- Granulated sugar
- Cream of tartar
How to make the recipe
Preheat the oven to 350°F. Cover an 8-inch square baking pan with parchment or foil, allowing it to extend over both ends.
Make the crust
In a food processor, combine the flour, sugar, and salt and pulse to mix. Add the butter and pulse until fine crumbs form.
Spread the mixture in the baking pan and press down to create an even layer.
Cook in the oven until set and golden brown, normally about 25 minutes. Remove to a wire rack to allow to cool.
Make the filling
In a large saucepan, combine the eggs, yolks, sugar, zest and juice, and salt. Simmer for 3 minutes while stirring constantly.
Reduce heat to low and simmer, whisking frequently, until thickened, about 8 minutes. Remove from the heat.
Pour the curd over the crust and smooth out any wrinkles. Cover with aluminum foil and bake for 10 minutes.
Remove from the oven and let cool completely. Refrigerate for at least 1 hour or overnight, or up to three days.
Meringue frosting
When you are ready to serve, make the frosting. Carefully remove the parchment from the bottom of the bars and transfer it to a baking sheet using a large, wide spatula.
In a metal mixing bowl, beat the egg whites, sugar, vanilla, and salt with a handheld mixer.
Set it over a pan of simmering water but make sure the bottom doesn't touch the water. Whisk until the sugar is dissolved and the mixture is warm to the touch, usually 3-4 minutes.
Remove from the water and beat on high speed until the mixture is glossy and stiff, usually about 5 minutes, before spooning the frosting over the filling and spreading to cover.
Finish the bars
Use a kitchen torch or a broiler to brown the meringue then pop in the refrigerator until serving.
To portion, use a knife dipped in hot water to cut into squares. Usually, 12 portions will be a nice number from this recipe but it is up to you.
Storing the recipe
You can store the lemon meringue bars in the refrigerator for 3-4 days in an airtight container.
I would avoid freezing them as the meringue will likely melt away and not be very tasty afterward.
Making meringue tips
Keep any yolk out of the whites. The fat in the yolks can interfere whipping the whites to a light and fluffy consistency. To avoid this, separate each egg over a small bowl to be sure the white is free of egg yolk before combining with other whites. Also, the yolks are less likely to break if you separate the eggs while they’re cold.
Use a clean, dry mixing bowl and beaters. Be sure the bowl you are using to whip the whites is clean and dry, as any soap residue or water can interfere with whipping.Beat until stiff. The peaks of the beaten egg whites should stand straight up when the beaters are lifted
Lemon Bars with Meringue Recipe
Ingredients
For the Crust
- 1 cup all-purpose flour
- ¼ cup confectioners' sugar
- 1 stick ½ cup unsalted butter chilled and cut into small pieces
- ¼ tsp. Salt
For the Filling
- 3 large eggs
- 8 large egg yolks
- 1 ⅓ cups granulated sugar
- 1 Tbs. grated lemon zest
- 1 ¼ cups fresh lemon juice
- Pinch salt
For the Meringue Frosting
- 4 large egg whites
- ½ cup granulated sugar
- ½ tsp. cream of tartar
Instructions
- Preheat the oven to 350°F. Line an 8-inch square baking pan with parchment or foil, letting it extend over the pan at two ends.
Make the Crust
- In a food processor, combine the flour, sugar, and salt and pulse to blend. Add the butter and pulse until fine crumbs form. Scatter the mixture in the prepared pan, and then press into an even layer. Bake until set and lightly golden brown, about 25 minutes. Remove to a wire rack to cool.
Make the Filling
- In a large saucepan, whisk together the eggs, yolks, sugar, zest and juice, and salt. Cook, whisking constantly until warm to the touch, about 3 minutes. Increase the heat to medium-low and continue to cook, whisking until thickened, about 8 minutes. Remove from the heat. Pour the curd over the crust and spread evenly. Cover with foil and bak 10 minutes. Remove to a wire rack, uncover, and let cool. When cool, cover and refrigerate for at least 1 hour, or up to 3 days.
- When ready to serve, make the meringue frosting. Carefully remove the parchment from the bottom of the bars and, using a large wide spatula, transfer the bars to a baking sheet.
- Whisk together the egg whites, sugar, vanilla, and salt in the metal bowl of a stand mixer. Set it over a pan of simmering water, (so the bottom doesn't tough the water) and whisk until the sugar is dissolved and the mixture is warm to the touch, 3 to 4 minutes. Remove from the water and beat on high speed until glossy and stiff, about 5 minutes. Spoon the frosting over the filling, gently spreading to cover.
Finish the Bars
- When you’re ready to finish, use a kitchen torch or your oven’s broiler to brown the meringue. Refrigerate until ready to serve. Use a knife dipped into hot water to cut bars into 12 squares, depending on how large you want them.
Notes
Lemon Coconut Impossible Pie
Lemon Cheesecake with Mixed Berry Topping
Kitty says
I made these bars for a party and they were a big hit!