Lemon Icebox Cake

5 from 2 votes

This no-bake lemon icebox cake layers of graham crackers, homemade lemon diplomat cream, and airy whipped cream for a bright citrus dessert perfect for warm Spring and Summer days!

Prep Time30

Waiting time4

Total Time4 30

Course: Dessert

Cuisine: American

Servings:

Calories: 606kcal

Author: Katalin Nagy

Equipment

Ingredients

Lemon Diplomat Cream

250 g Granulated sugar
160 g Egg yolk approximate yolk of 8 eggs
4 tablespoons Lemon juice freshly squeezed
50 g Corn starch
50 g All purpose flour
½ tablespoon Vanilla extract
960 g Whole milk 3% fat
Peel of 1-2 lemons
110 g Unsalted butter 82% fat, at room temperature
230 g Heavy cream 36% fat content, cold

To assemble

14 oz Graham cracker 1 package, 400g. Can be substituted with an equal amount of Digestive biscuits.

Whipped cream topping

460 g Heavy cream 36% fat, use it very cold
60 g Powdered sugar sifted

Metric - US Customary

Instructions

Lemon Diplomat Cream

Whisk the sugar, egg yolks and lemon juice in a bowl for 1-2 minutes until fluffy. Then, add the cornstarch, flour, and vanilla, and mix until smooth.
In a saucepan, heat the milk over medium heat with the lemon peels (to infuse) until it begins to simmer (but not boil). Remove the lemon peels, then, gradually pour the hot milk into the egg yolk mixture while whisking constantly to temper the yolks.
Return the mixture to the saucepan and cook over medium heat, stirring continuously, until it thickens (about one minute after boiling). If the mixture is lumpy, continue whisking until smooth. Remove from heat and strain if needed.
Gradually add the softened butter in chunks, mixing until fully incorporated.
Cover the lemon pastry cream with plastic wrap and let it come to room temperature while preparing a 9x13 / 22x33cm baking dish and your Graham crackers.
Once the cream is cooled to room temperature, place very cold 36% fat-content heavy cream in a mixing bowl and use an electric hand mixer to whip the mixture for about 2-3 minutes until fluffy. Do not overwhip.
Gently loosen the lemon pastry cream with a few quick whisks, then carefully, using a rubber spatula, fold in the whipped heavy cream, ensuring the mixture stays light and airy.

Assemble

To assemble, divide the graham crackers into 3 (as there will be three layers) and the diplomat cream into 2 (as there will be two layers).
Place one-third of the graham crackers in a single, tight layer at the bottom of a 9x13-inch baking pan. Break the crackers as necessary to fit. Evenly spread half of the lemon diplomat cream on top. Add a second layer of graham crackers on top of this. Then, spread the remaining lemon diplomat cream. Finally, top with a third layer of graham crackers.
Refrigerate while preparing the whipped cream layer.

Whipped cream layer

Place very cold heavy cream with the sifted powdered sugar into a mixing bowl. Use an electric hand mixer to whip the mixture for about 2-3 minutes until fluffy.
Spread the whipped cream layer evenly over the graham cracker layer. Chill the cake for 4 hours before serving, for the layers to soften. Serve the Lemon icebox cake after 4 hours of chilling.
Decorate with lemon slices, fresh basil or mint, and a sprinkle of lemon zest.

How to store

Any leftovers can be covered and refrigerated for 2 days. The layers will further soften over time. Do not freeze this cake, as neither the lemon diplomat cream nor the whipped cream layer freezes well.

Notes

INGREDIENT NOTES:

Measure your ingredients with a digital scale for accuracy.
Graham crackers can be substituted with digestive biscuits, ladyfingers, Biscoff cookies, or similar not-too-hard, not-too-soft cookies.
For extra flavor, you can infuse the lemon peels in the milk overnight in the refrigerator.
Good quality butter and pure vanilla extract are the heart of making pastry cream. Use high-quality 82% fat-content European butter, the best quality vanilla you can access, as well as freshly squeezed lemon juice.
For the whipped cream, high-fat (36%) heavy cream is recommended, and it should be used very cold. Cream with a lower fat content might not whip up properly.

TECHNIQUE NOTES:

Use a small/medium-sized saucepan with good heat distribution to avoid burning the milk when making the cream.
Whipped cream frosting is very easy to overwhip. When whipping, stop as soon as the mixture reaches a fluffy consistency and forms stiff peaks. It won't get stiffer after this point. In fact, if you overbeat it, it will only get runnier and then break.
The cake will soften over time. I personally like it on the first day, as it can get a bit too moist after that.

Nutrition