Created as a love letter to the number one lemon lover in my life, this cake has yet to disappoint a single citrus fan. Soft lemon chiffon cake is soaked with lemon syrup and layered with tart lemon curd, and then the whole thing is frosted with lemon curd buttercream. Use fragrant Meyer lemons if you can get them—that sends this cake completely over the top.
Makes one 9-inch 4-layer cake
Difficulty: Hard
Make Ahead and Storage: The cakes can be wrapped tightly in plastic wrap and refrigerated for up to 1 day, or double-wrapped and frozen for up to 3 months; thaw at room temperature before using. The syrup can be made up to 1 week ahead and refrigerated airtight. The frosting can be made up to 1 week ahead and refrigerated airtight (see sidebar for how to reconstitute before using). Slices can be refrigerated tightly wrapped in plastic for up to 2 days.
1. Preheat the oven to 325°F / 162°C, with a rack in the middle. Grease and flour two 9-inch round cake pans.
2. Make the cakes: Sift together the cake flour, baking powder, and salt into a medium bowl. In a container with a spout (such as a 2-cup liquid measure), whisk together the oil, milk, vanilla, and lemon extract.
3. In the bowl of a stand mixer fitted with the whisk attachment (or in a large bowl, using a hand mixer), whip the egg yolks on medium speed until slightly pale, 1 to 2 minutes. Gradually add 198 g / 1 cup of the granulated sugar and whip the mixture on medium-high speed until it becomes pale and thick and has quadrupled in volume, 4 to 5 minutes. Reduce the speed to low and add the lemon zest, then whip for 1 minute more to help stabilize the foam.
4. Gradually add the milk mixture to the egg yolk mixture in a slow steady stream, mixing on low speed to combine.
5. Sprinkle about one quarter of the flour mixture over the egg yolk mixture and mix on low speed just until incorporated. Add the remaining flour in 3 more additions, mixing just until incorporated.
6. In a clean, dry mixer bowl or other large bowl, combine the egg whites with the cream of tartar and, using the mixer (fitted with the cleaned and dried whisk attachment/beaters), beat on low speed until lightly foamy, 1 to 2 minutes. Turn the speed up to medium-high and whip the egg whites to soft peaks, 4 to 5 minutes. Gradually add the remaining 100 g / ½ cup granulated sugar and continue whipping the mixture until it reaches medium peaks, 1 to 2 minutes more.
7. Fold about one quarter of the whipped egg whites into the batter, mixing thoroughly (this first addition helps temper the batter, making it easier to incorporate the rest of the whites without deflating them). Add the remaining whites in 2 or 3 more additions, gently folding them in just until incorporated.
8. Divide the batter between the prepared pans (about 652 g per pan). Bake until the cakes spring back slightly when touched in the center, 50 to 55 minutes. Cool the cakes in the pans for 10 to 15 minutes, then turn out onto a wire rack to cool completely.
9. Meanwhile, make the lemon syrup: Combine the lemon juice and granulated sugar in a small saucepan and bring to a boil over medium-high heat, stirring to help dissolve the sugar. Set aside to cool to room temperature.
10. Make the buttercream: Start with an Italian meringue. Place the egg whites in the bowl of a stand mixer fitted with the whisk attachment (or use a large bowl with a hand mixer). In a medium saucepan, combine the sugar and the water and bring to a boil over medium heat, stirring constantly to help the sugar dissolve. Once the mixture comes to a boil, stop stirring (if any sugar clings to the sides, use a pastry brush dipped in cool water to brush it back down into the syrup). Attach a candy thermometer to the side of the saucepan (or have an instant-read thermometer at the ready).
11. When the syrup reaches 235°F / 113°C, begin whipping the egg whites on medium-high speed. (The goal is to get the whites to soft peaks by the time the sugar reaches 240°F / 115°C.)
12. When the whites reach soft peaks and the syrup has reached 240°F / 115°C, with the mixer running, pour the syrup into the whites in a slow, steady stream, then continue whipping until the meringue has reached its full volume (it will be very white and glossy) and the bowl is no longer warm to the touch, 5 to 6 minutes.
13. With the mixer running on medium speed, gradually add the butter, 1 to 2 tablespoons at a time, waiting until each addition is incorporated before adding more. Add the lemon curd and mix to combine.
14. Transfer about one quarter of the buttercream to a disposable pastry bag or a heavy-duty zip-top bag and snip off a ½-inch opening at the tip/one corner.
15. Assemble the cake: Use a long serrated knife to level the tops of the cakes and then slice each one horizontally in half to create a total of 4 layers (see Cutting Cakes Into Layers).
16. Place one layer on a turntable or cake stand (or a platter) and brush the top evenly with lemon syrup, fully soaking the layer. Pipe a ring of buttercream all around the outer edge of the cake. Scoop ½ cup of the lemon curd into the center of the ring and use a small offset spatula to spread it evenly. Repeat with the remaining cake layers, more buttercream, and the remaining lemon curd. Leave the top layer naked.
17. Apply a crumb coat of frosting (see Frosting Techniques) to the top and sides of the cake and refrigerate to set, 15 to 30 minutes.
18. Frost the sides and top of the cake with an offset spatula (for more detailed frosting instructions, see Frosting Techniques). Refrigerate the cake for at least 15 minutes before slicing (it will slice more cleanly this way).
✻ Why It Works
Whipping the yolks and whites separately provides double aeration for maximum lightness, with the whipped yolks serving as a strong base to which the other ingredients can be added to form the batter. The egg whites are folded in at the end to take the cake to towering, light-as-air heights.
Piping a ring of frosting around the outer edge of each cake layer acts as a sort of “retaining wall” to help keep the soft lemon curd from oozing out the sides as you layer the cake.
★ Pro Tip
Many recipes for delicate cakes like this call for the dry ingredients to be folded in by hand, and that is generally my preferred method. But for many people, this can be tricky to do without overmixing the batter. Using the mixer (carefully and minimally) allows you to achieve a homogeneous batter faster, which means a better chance for a loftier cake. Once you’ve made a chiffon cake successfully, try folding the ingredients together by hand for an even lighter cake!