Lemon Square Cake

Ingredients

• 200 g Almond flour (Sift to avoid lumps)
• 100 g Brown sugar (Brown sugar, adds moistness)
• 80 g Powdered sugar (Sift before use)
• 1 pincée Salt (Fine sea salt)
• 4 unités Eggs (3 yolks + 1 white reserved for the sponge, the remaining 3 whites for the meringue)
• 2 citron(s) Lemon zest (Finely grated zest)
• 120 g Lemon confit (Very concentrated confit, provides intense lemon flavor)
• 5 g Baking powder (About 1 teaspoon, sifted)
• 250 g Unsalted butter (for the sponge) (At room temperature, then melted for incorporation)
• 250 g Unsalted butter (for the buttercream) (Softened butter, tempered)
• 150 g Granulated sugar (for the meringue) (Added to egg whites)
• 30 g Powdered sugar (for the meringue) (Incorporated at the end of mixing)
• 200 ml Whole milk (For the custard)
• 2 unités Egg yolks (for the custard) (At room temperature)
• 100 g Granulated sugar (for the custard) (Divided into two equal parts)
• 200 g White chocolate (Good quality, broken into pieces)
• 20 ml Grape seed oil (To thin the white glaze)
• 1 citron vert Lime zest (For final decoration)
• 1 citron Yellow lemon zest (For final decoration)

Instructions

1. Prepare the sponge

   Sift the almond flour, brown sugar, powdered sugar and baking powder into a bowl. Add the salt, egg yolks, the reserved white, lemon zest and lemon confit. Incorporate the melted butter and mix until a homogeneous batter is obtained.

   Time: PT20M

2. Whip the egg whites

   In a clean bowl, whip the 3 egg whites with the brown sugar until a firm meringue forms, then add the sifted powdered sugar and continue until glossy peaks form.

   Time: PT15M

3. Fold the whites into the batter

   Add one third of the whipped whites to the sponge batter, mix gently to loosen the mass, then fold in the remaining whites in two batches, lifting the batter with a spatula.

   Time: PT5M

4. Bake the sponge

   Pour the batter into the pan previously lined with parchment paper, smooth the surface and bake.

   Time: PT34M

   Temperature: 160°C

5. Cool the sponge

   Remove the cake from the oven, let it rest 10 min in the pan, then unmold onto a rack and let cool completely.

   Time: PT20M

6. Make the butter‑lemon confit mixture

   Melt 250 g of unsalted butter in a small saucepan, add the lemon confit and stir until a smooth mass is obtained.

   Time: PT5M

7. Prepare the custard

   In a saucepan, heat the milk with half of the sugar (50 g). In a bowl, whisk the 2 egg yolks with the remaining sugar (50 g). Pour the hot milk over the yolks while whisking, return everything to the saucepan and cook over low heat until 82‑84 °C, without boiling.

   Time: PT10M

8. Emulsify the lemon buttercream

   Pour the hot butter‑lemon confit into the custard while whisking at medium speed until the butter is fully incorporated. Add the remaining butter (250 g) in pieces, then continue whisking until a smooth, glossy cream forms. Fold in the remaining lemon confit to intensify the flavor.

   Time: PT10M

9. Rest the buttercream

   Let the buttercream sit at room temperature for 15 minutes so it becomes pliable and easy to spread.

   Time: PT15M

10. Whip the French meringue

    Whip the remaining 3 egg whites with the granulated sugar (150 g) until stiff peaks form, then fold in the sifted powdered sugar (30 g) and whisk a few more seconds.

    Time: PT15M

11. Shape the fairy fingers

    Fill a pastry bag fitted with a 10‑12 mm plain tip and pipe meringue strips about 5 cm long onto a sheet lined with parchment paper.

    Time: PT10M

12. Bake the meringue fingers

    Bake the meringue strips at 95 °C for 1 hour, with the oven door slightly ajar to let moisture evaporate.

    Time: PT1H

    Temperature: 95°C

13. Prepare the white chocolate glaze

    Melt the white chocolate with the grape seed oil in a bain‑marie or over low heat, stirring until a smooth, slightly warm texture is achieved.

    Time: PT5M

14. Assemble the cake

    Cut the cooled sponge into three equal layers (about 1.5 cm thick). Spread 200 g of lemon buttercream on the first layer, place the second layer, spread 400 g of buttercream, place the third layer and cover everything with a thin layer of buttercream to smooth the edges.

    Time: PT20M

15. Glaze and decorate

    Pour the white chocolate glaze over the cake, letting it flow gently down the sides. Arrange the meringue fingers on top before the glaze sets. Sprinkle with yellow and green lemon zest for the final touch.

    Time: PT10M

16. Finish and rest

    Place the cake in the refrigerator for 30 minutes so the glaze sets and the buttercream stabilizes.

    Time: PT30M

Nutrition Facts

Calories

350

Protein

5 g

Carbohydrates

45 g

Fat

18 g

Fiber

2 g

Ingredient Substitutions

• Instead of Almond flour: Wheat flour (changes flavor)
• Instead of Brown sugar: White sugar
• Instead of Powdered sugar: Very fine granulated sugar
• Instead of Lemon zest: Orange zest
• Instead of Lemon confit: Sweet lemon coulis
• Instead of Baking powder: Rising powder
• Instead of Unsalted butter (for the sponge): Vegetable margarine (changes flavor)
• Instead of Unsalted butter (for the buttercream): Half-salted butter (adjust salt)
• Instead of Granulated sugar (for the meringue): Powdered sugar
• Instead of Whole milk: Semi-skimmed milk
• Instead of Granulated sugar (for the custard): Powdered sugar
• Instead of White chocolate: Milk chocolate (changes flavor)
• Instead of Grape seed oil: Sunflower oil

Equipment Needed

• Mixing bowl(s)
• Electric mixer
• Silicone spatula
• Sieve
• 30 × 40 cm baking frame
• Parchment paper
• Cooking thermometer
• Saucepan
• Whisk
• Pastry bag with 10‑12 mm plain tip
• Cooling rack
• Slicing knife
• Cutting board
• Small saucepan for the glaze
• Offset spatula

Critical Steps — Do Not Skip

• Baking the sponge at 160°C
• Assembly and emulsification of the buttercream (butter and custard temperatures)
• Firm whipping of the French meringue
• Low‑temperature baking of the meringue fingers
• Warm white chocolate glaze to avoid melting the meringue

Chef Tips from the Video

• Use untreated organic lemon for the zest to avoid bitterness.
• Sifting the powdered sugar into the meringue prevents grains and yields a smoother texture.
• For an ultra‑shiny finish, polish the glaze with a small warm butter knife just before serving.

Troubleshooting

Storage

Refrigerator: Store the whole cake, well covered, in the refrigerator for up to 3 days.

Freezer: Wrap each square individually in cling film then place in a freezer bag; keep up to 1 month.

Room temperature: At room temperature, the cake keeps for a maximum of 6 hours (risk of glaze softening).

Make-Ahead Tips

• Bake the sponge and let it cool completely before storing it in cling film (up to 2 days).
• Prepare the lemon buttercream the day before and keep it refrigerated; bring it to room temperature before assembly.
• The meringue fingers can be baked ahead and stored in an airtight container at room temperature for 2 days.