Ingredients

For the Baked Meringue Swirls/Discs:
• 3 egg whites (90 g)
• 3/4 cup (150 g) sugar
• A drop soft gel paste color, yellow
• You will also need:
• A large pastry bag
• Decorating tip #1A
• A small paintbrush
For the Lemon Curd:
• 4 lemons (or 6 Meyer lemons), preferably organic
• 2 whole eggs plus 4 egg yolks (set whites aside for buttercream)
• 1 cup sugar (200 g)
• 4 tablespoons (60 g) unsalted butter, at room temperature and cut into small even cubes
For the Lemon Swiss Meringue Buttercream:
• 7 egg whites (210 g)
• 1-1/2 cups (300 g) sugar
• Pinch of salt
• 2 cups (454 g) unsalted butter, softened and cut into cubes
• 1/4 cup (60 ml) lemon curd
• 1 teaspoon (5 ml) pure vanilla extract
• Few drops of soft gel paste colour, yellow (I used electric yellow)
For the Lemon Cake:
• 3/4 cup (170 g) unsalted butter, softened
• 2 cups (400 g) sugar
• 6 eggs, separated
• 2 cups (270 g) all-purpose flour
• 3/4 teaspoon (4 g) baking soda
• 1/2 teaspoon(4 g) salt
• 2 tablespoons (30 ml) lemon juice
• 2 teaspoons (10 ml) pure vanilla extract
• 1/2 teaspoon (2.75 ml) lemon extract
• 2 tablespoons (30 ml) lemon zest
• 3/4 cup (180 ml) plain yogurt, at room temperature
• baked meringue swirls, for decorating
• lemon drop candy, for decorating

Instructions

For the Baked Meringue Swirls/Discs:
1. Preheat oven to 200°F. Line two baking sheets with parchment paper and set aside. Wipe the bowl of an electric mixer and the whisk attachment with paper towel and lemon juice, to remove any trace of grease.
2. Add egg whites and sugar to the mixer bowl and fit onto the top of a medium saucepan filled with about 1-inch of simmering (not boiling) water. (Be sure the bottom of your bowl is not touching the water.) Whisk constantly but gently, until temperature reaches 140°F, or if you don’t have a candy thermometer, until the sugar has completely dissolved and the egg whites are hot.
3. Dry the underside of the mixer bowl and transfer to your stand mixer. Whip using the whisk attachment until the meringue is thick and glossy and has reached the stiff peak stage.
4. While the meringue is whipping in the mixer, fit your decorating bag with a plain round pastry tip. Fold over a cuff at the top of the pastry bag and paint 3, equally-spaced, thin lines of yellow gel colour using your fine paint brush (you can use any paint brush, but it should only be one you designate for food) from the pastry tip up toward the cuff.
5. Fill the bag with your meringue (no more than 2/3 full) and pipe 1-1/2-inch swirls onto one of the lined baking sheets, spacing them about 1-inch apart. (These will be used to decorate top of cake). On the second baking sheet, pipe the remaining meringue into flat discs, about 2-inches in diameter, spacing them about 1" apart. (These will be used on top of the filling inside the assembled cake.)
6. Bake for 60 minutes, rotating the trays after 30 minutes. Lower the oven to 175°F and bake until dry, about 40 minutes more. Keep in an airtight container until needed.
For the Lemon Curd:
7. Wash lemons really well (with a bristled brush under cold water) and using a zester, remove all of the coloured portion of the peel from the fruit (not the white pith–it’s bitter!) into a bowl or onto a piece of wax paper. Rotate fruit as necessary to get as much of the zest off. Repeat until you have 2 teaspoons (30 ml) of the zest, and set aside.
8. Slice the lemons in half crosswise (I find room temperature citrus is best for juicing) using a sharp knife, and extract as much of the juice as you can using a citrus reamer, or I use a small, manual citrus juicer. (Just be sure to catch all of the juice in a bowl and to completely strain the seeds before using.) Repeat the juicing until you have 2/3 cup (160 ml) of the strained juice.
9. Get your double boiler ready by filling a saucepan with 1″ of water, then placing a metal bowl on top of the saucepan. You will need to ensure the bowl fits snugly into the top of the saucepan and that the bottom of the bowl doesn’t touch the water (important, or your eggs will cook). You can now remove the bowl and continue with making the curd.
10. Whisk the juice, whole eggs, egg yolks and sugar in the bowl until smooth. Add the butter cubes to the bowl, but don’t stir.
11. Heat the water in the saucepan over low heat until it simmers (not boils) and place the bowl atop the rim. Stirring gently, but constantly, using heatproof spatula or wooden spoon, cook until the curd has thickened and all of the butter has melted and is incorporated, about 10 minutes (this can vary). To test if the curd is thick enough, remove the spatula or spoon from the curd and check that it’s coated.
12. Strain the curd over a bowl using a fine-mesh sieve and then stir in the zest. Cover with plastic wrap pressed directly against the curd (to prevent a skin from forming) and chill for at least 3 hours (I like to chill it overnight). It also thickens up a bit more while chilling. Keep refrigerated.
For the Lemon Swiss Meringue Buttercream:
13. Wipe the bowl of an electric mixer with paper towel and lemon juice, to remove any trace of grease. Add egg whites, sugar and salt, and simmer over a pot of water (not boiling), whisking constantly but gently, until temperature reaches 160°F, or if you don't have a candy thermometer, until the sugar has completely dissolved and the egg whites are hot.
14. With whisk attachment of mixer, begin to whip until the meringue is thick, glossy, and the bottom of the bowl feels neutral to the touch (this can take up to 10 minutes or so). *Don't begin adding butter until the bottom of the bowl feels neutral, and not warm.
15. Switch over to paddle attachment and, with mixer on low speed, add butter cubes, one at a time, until incorporated. Increase mixer speed to medium and whip until it has reached a silky smooth texture (if curdles, keep mixing and it will come back to smooth). *If mixture is too runny, refrigerate for about 15 minutes and continue mixing with paddle attachment until it comes together. Add lemon curd and vanilla, continuing to beat on medium speed until well combined. Add yellow soft gel paste colour until desired shade of yellow is achieved.
For the Lemon Cake:
16. Preheat oven to 350°F (180°C). Grease, line with parchment and flour three round 8-inch pans. I use Parchment Paper Circles for ease. In the bowl of a mixer fitted with the paddle attachment, cream butter and 1 cup (200 g) of the sugar on medium high speed until very pale and fluffy, about 5 minutes. In a medium bowl, sift flour, baking soda and salt. Set aside.
17. Lower mixer speed to medium low and add the egg yolks, one at a time, scraping the sides of the bowl with a rubber spatula after each addition. Add lemon juice, vanilla, lemon extract and lemon zest and beat until incorporated, about 30 seconds. With mixer running, add dry ingredients. Add yogurt, scraping down the sides of the bowl to make sure everything is well incorporated.
18. In another grease-free bowl, (or if you're lucky enough to have another mixer bowl) whip egg whites and remaining cup of sugar until they reach stiff peak stage. Fold meringue into batter until just combined, and divide batter evenly among the three prepared pans. Use a digital kitchen scale to weigh pans to ensure even layers, if possible (425 g of batter for each layer).
19. Bake first two layers 2" apart in center of oven on top of a baking sheet until a cake tester comes clean when inserted into the center, about 25 minutes. Be careful to not over-bake -- check cake at 20 minutes, but not before, and once you feel it’s almost ready, set the timer for 2 minute intervals. Repeat with final cake layer. Let cool on racks for 10 minutes before loosening the sides with a small metal spatula, and invert onto greased wire racks. Gently turn cakes back up, so the tops are up and cool completely.
20. Wrap tightly and store at room temperature for up to 2 days, refrigerator for up to 5 days, or frozen for up to 2 months. Best enjoyed day 1 or 2.
Assembly of the Lemon Delight Layer Cake:
21. Trim any doming or top crust and side crust from cake layers using a very sharp serrated knife (I use the Mac Bread Knife for all of my cake trimming, splitting, etc.).
22. Use a cake turntable for filling, frosting and decorating, if a possible. Place a small dollop of frosting in the center of a cake plate or 8″ round thin foil-covered cake board, and place the bottom cake layer on top, trimmed side up (face up).
23. Pipe a dam (a rim around the top perimeter of the cake layer) of lemon curd buttercream around the cake layer using a large round Pastry Tip fitted inside a Decorating Bag. Then pipe another smaller circle of buttercream a few inches toward the center. Spoon lemon curd into the open spaces and spread evenly with a small offset palette knife, taking care to keep the curd within the dam (otherwise it will ooze out of the sides of the cake). Gently place cover the filling with a layer of the flat baked meringue discs, breaking them into smaller pieces if necessary to cover most of the layer.
24. Repeat with second cake layer and more buttercream, lemon curd and meringue discs. Place final cake layer, trimmed side down. Look straight down from above cake and be sure the layers are all lined up, shifting gently if necessary. Cover with plastic wrap and chill for at least 30 minutes.
25. Remove from fridge and put a generous scoop of buttercream on top, spreading evenly with a small offset palette knife and working your way down the sides until you have a thin layer of frosting over the entire cake (crumb-coat). Chill until set, another 30 minutes.
26. Remove from refrigerator and covering the cake in another layer of buttercream, but this time using a thicker layer of buttercream and creating a smooth finish.
27. For the top of the cake, using your decorating bag fitted with the large round tip , 2/3 full with buttercream, pipe 8 small swirls, evenly spaced. Top each swirl with a baked meringue swirls, and fill the spaces in between with lemon drop candy. Gently spoon a layer of lemon curd on top of the cake, using a toothpick to pull the curd to the inside edges of the candy and swirls.
28. Store finished cake covered in refrigerator (due to the lemon curd filling), but serve at room temperature (you can remove from refrigerator several hours ahead of serving).

Notes